Photoresponsive Molecular Recognition and Adhesion of Vesicles in a Competitive Ternary Supramolecular System

NARCIS (Netherlands)

Nalluri, Siva Krishna Mohan; Bultema, Jelle B.; Boekema, Egbert J.; Ravoo, Bart Jan

A competitive photoresponsive supramolecular system is formed in a dilute aqueous solution of three components: vesicles of amphiphilic alpha-cyclodextrin host 1a, divalent p-methylphenyl guest 2 or divalent p-methylbenzamide guest 3, and photoresponsive azobenzene monovalent guest 5. Guests 2 and 3

A chiroptical switch based on supramolecular chirality transfer through alkyl chain entanglement and dynamic covalent bonding.

Science.gov (United States)

Lv, Kai; Qin, Long; Wang, Xiufeng; Zhang, Li; Liu, Minghua

2013-12-14

Chirality transfer is an interesting phenomenon in Nature, which represents an important step to understand the evolution of chiral bias and the amplification of the chirality. In this paper, we report the chirality transfer via the entanglement of the alkyl chains between chiral gelator molecules and achiral amphiphilic Schiff base. We have found that although an achiral Schiff base amphiphile could not form organogels in any kind of organic solvents, it formed co-organogels when mixed with a chiral gelator molecule. Interestingly, the chirality of the gelator molecules was transferred to the Schiff base chromophore in the mixed co-gels and there was a maximum mixing ratio for the chirality transfer. Furthermore, the supramolecular chirality was also produced based on a dynamic covalent chemistry of an imine formed by the reaction between an aldehyde and an amine. Such a covalent bond of imine was formed reversibly depending on the pH variation. When the covalent bond was formed the chirality transfer occurred, when it was destroyed, the transfer stopped. Thus, a supramolecular chiroptical switch is obtained based on supramolecular chirality transfer and dynamic covalent chemistry.

Thermoresponsive Interplay of Water Insoluble Poly(2-alkyl-2-oxazolines Composition and Supramolecular Host–Guest Interactions

Directory of Open Access Journals (Sweden)

Victor R. de la Rosa

2015-04-01

Full Text Available A series of water insoluble poly[(2-ethyl-2-oxazoline-ran-(2-nonyl-2-oxazoline] amphiphilic copolymers was synthesized and their solubility properties in the presence of different supramolecular host molecules were investigated. The resulting polymer-cavitand assemblies exhibited a thermoresponsive behavior that could be modulated by variation of the copolymer composition and length. Interestingly, the large number of hydrophobic nonyl units across the polymer chain induced the formation of kinetically-trapped nanoparticles in solution. These nanoparticles further agglomerate into larger aggregates at a temperature that is dependent on the polymer composition and the cavitand type and concentration. The present research expands the understanding on the supramolecular interactions between water insoluble copolymers and supramolecular host molecules.

Inclusion of 5-[4-(1-dodecanoylpyridinium)]-10,15,20-triphenylporphine in supramolecular aggregates of cationic amphiphilic cyclodextrins: physicochemical characterization of the complexes and strengthening of the antimicrobial photosensitizing activity.

Science.gov (United States)

Ferro, Stefania; Jori, Giulio; Sortino, Salvatore; Stancanelli, Rosanna; Nikolov, Peter; Tognon, Giuseppe; Ricchelli, Fernanda; Mazzaglia, Antonino

2009-09-14

Recent findings suggest that visible light-promoted photooxidative processes mediated by sensitizers of appropriate chemical structure could represent a useful tool for properly addressing the problem of the increasing occurrence of infectious diseases caused by multiantibiotic-resistant microbial pathogens. The monocationic meso-substituted porphyrin 5-[4-(1-dodecanoylpyridinium)]-10,15,20-triphenyl-porphine (TDPyP) complexed into supramolecular aggregates of cationic amphiphilic beta-cyclodextrin (SC(6)NH(2)) (mean diameter = 20 nm) appeared to be endowed with favorable properties to act as a photosensitizing agent, including a very high quantum yield (Phi(Delta) = 0.90) for the generation of the highly reactive oxygen species, singlet oxygen ((1)O(2)). Although the yield of (1)O(2) generation was comparable to that obtained after TDPyP incorporation into cationic unilamellar liposomes of N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) SC(6)NH(2)-bound TDPyP was more active than DOTAP-bound TDPyP in photosensitizing the inactivation of the Gram-positive methicillin-resistant bacterium Staphylococcus aureus (MRSA). At variance with DOTAP-bound TDPyP, photoactivated SC(6)NH(2)-bound TDPyP was efficient also in photokilling Gram-negative bacterial pathogens, such as Escherichia coli . These observations are in agreement with the well-known photobactericidal effect of positively charged porphyrin derivatives, which can be markedly enhanced after incorporation into carriers with multiple positive charges. In addition, transmission electron microscopy studies revealed that potentiation of the TDPyP-mediated photobactericidal effect by incorporation into SC(6)NH(2) is a consequence of the carrier's ability to promote an efficient crossing of the very tightly organized three-dimensional architecture of the bacterial outer wall by the embedded porphyrin so that a prompt interaction between the short-lived photogenerated (1)O(2) and the nearby

Heparin-binding peptide amphiphile supramolecular architectures as platforms for angiogenesis and drug delivery

Science.gov (United States)

Chow, Lesleyann W.

A fascinating phenomenon in nature is the self-assembly of molecules into a functional, hierarchical structure. In the past decade, the Stupp Laboratory has developed several classes of self-assembling biomaterials, one of which is the synthetic peptide amphiphile (PA). Self-assembling PAs are attractive and versatile biomolecules that can be customized for specific applications in regenerative medicine. In particular, a heparin-binding peptide amphiphile (HBPA) containing a specific heparin-binding peptide sequence was used here to induce angiogenesis and serve as a delivery vehicle for growth factors and small hydrophobic molecules. Throughout this dissertation, the HBPA/heparin system is used in different architectures for a variety of regenerative medicine applications. In one aspect of this work, hybrid scaffolds made from HBPA/heparin gelled on a poly(L-lactic acid) (PLLA) fiber mesh were used to promote angiogenesis to facilitate pancreatic islet transplantation for the treatment of type 1 diabetes. Delivery of growth factors with HBPA/PLLA scafflolds increased vessel density in vivo and correlated with improved transplant outcomes in a streptozotocin-induced diabetic mouse model. Soluble HBPA nanofiber architectures were also useful for islet transplantation applications. These nanofibers were used at concentrations below gelation to deliver growth factors into the dense islet cell aggregate, promoting cell survival and angiogenesis in vitro. The nanostructures infiltrated the islets and promoted the retention of heparin and growth factors within the islet. Another interesting growth factor release system discussed here is the HBPA membrane structure. HBPA was found to self-assemble with hyaluronic acid, a large biopolymer found in the body, into macroscopic, hierarchically-ordered membranes. Heparin was incorporated into these membranes and affected the membrane's mechanical properties and growth factor release. Human mesenchymal stem cells were also shown

Directed supramolecular surface assembly of SNAP-tag fusion proteins

NARCIS (Netherlands)

Uhlenheuer, D.A.; Wasserberg, D.; Haase, C.; Nguyen, H.; Schenkel, J.H.; Huskens, J.; Ravoo, B.J.; Jonkheijm, P.; Brunsveld, L.

2012-01-01

Supramolecular assembly of proteins on surfaces and vesicles was investigated by site-selective incorporation of a supramolecular guest element on proteins. Fluorescent proteins were site-selectively labeled with bisadamantane by SNAP-tag technology. The assembly of the bisadamantane functionalized

Directed Supramolecular Surface Assembly of SNAP-tag Fusion Proteins

NARCIS (Netherlands)

Uhlenheuer, D.A.; Wasserberg, D.; Haase, C.; Nguyen, Hoang D.; Schenkel, J.H.; Huskens, Jurriaan; Ravoo, B.J.; Jonkheijm, Pascal; Brunsveld, Luc

2012-01-01

Supramolecular assembly of proteins on surfaces and vesicles was investigated by site-selective incorporation of a supramolecular guest element on proteins. Fluorescent proteins were site-selectively labeled with bisadamantane by SNAP-tag technology. The assembly of the bisadamantane functionalized

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

KAUST Repository

Fathalla, Maher; Strutt, Nathan; Srinivasan, Sampath; Katsiev, Khabiboulakh; Hartlieb, Karel J.; Bakr, Osman; Stoddart, J. Fraser

2015-01-01

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.

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.

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.

Tuning peptide amphiphile supramolecular structure for biomedical applications

Science.gov (United States)

Pashuck, Eugene Thomas, III

The use of biomaterials in regenerative medicine has been an active area of research for more than a decade. Peptide amphiphiles, which are short peptide sequences coupled to alkyl tails, have been studied in the Stupp group since the beginning of the decade and been used for a variety of biomedical applications. Most of the work has focused on the bioactive epitopes places on the periphery of the PA molecules, but the interior amino acids, known as the beta-sheet region, give the PA nanofiber gel much of its mechanical strength. To study the important parameters in the beta-sheet region, six PA molecules were constructed to determine the influence of beta-sheet length and order of the amino acids in the beta-sheet. It was found that having beta-sheet forming amino acids near the center of the fiber improves PA gel stiffness, and that having extra amino acids that have preferences for other secondary structures, like alpha-helix decreased the gels stiffness. Using FTIR and circular dichroism it was found that the mechanical properties are influenced by the amount of twist in the beta-sheet, and PAs that have more twisted beta-sheets form weaker gels. The effect amino acid properties have on peptide amphiphile self-assembly where studied by synthesizining molecules with varying side group size and hydrophobicity. It was found that smaller amino acids lead to stiffer gels and when two amino acids had the same size the amino acid with the larger beta-sheet propensity lead to a stiffer gel. Furthermore, small changes in peptide structure were found to lead to big changes in nanostructure, as leucine and isoleucine, which have the same size but slightly different structures, form flat ribbons and cylindrical nanofibers, respectively. Phenylalanine and alanine were studied more indepth because they represent the effects of adding an aromatic group to amino acids in the beta-sheet regon. These phenylalanine PAs formed short, twisted ribbons when freshly dissolved in water

Evolution of heterogeneity accompanying sol-gel transitions in a supramolecular hydrogel.

Science.gov (United States)

Matsumoto, Yuji; Shundo, Atsuomi; Ohno, Masashi; Tsuruzoe, Nobutomo; Goto, Masahiro; Tanaka, Keiji

2017-10-18

When a peptide amphiphile is dispersed in water, it self-assembles into a fibrous network, leading to a supramolecular hydrogel. When the gel is physically disrupted by shaking, it transforms into a sol state. After aging at room temperature for a while, it spontaneously returns to the gel state, called sol-gel transition. However, repeating the sol-gel transition often causes a change in the rheological properties of the gel. To gain a better understanding of the sol-gel transition and its reversibility, we herein examined the thermal motion of probe particles at different locations in a supramolecular hydrogel. The sol obtained by shaking the gel was heterogeneous in terms of the rheological properties and the extent decreased with increasing aging time. This time course of heterogeneity, or homogeneity, which corresponded to the sol-to-gel transition, was observed for the 1st cycle. However, this was not the case for the 2nd and 3rd cycles; the heterogeneity was preserved even after aging. Fourier-transform infrared spectroscopy, small-angle X-ray scattering, and atomic force and confocal laser scanning microscopies revealed that, although the molecular aggregation states of amphiphiles both in the gel and sol remained unchanged with the cycles, the fibril density diversified to high and low density regions even after aging. The tracking of particles with different sizes indicated that the partial mesh size in the high density region and the characteristic length scale of the density fluctuation were smaller than 50 nm and 6 μm, respectively.

Relation between structure and organisation properties of new amphiphilic cyclodextrins

International Nuclear Information System (INIS)

Moutard, Stephane

2003-01-01

Since a number of years, special attention and efforts have been made to prepare amphiphilic cyclodextrins (CDs) with the objective to use them to obtain supramolecular assemblies as such or in the presence of preformed lipidic structures. The aim of these investigation is in both cases to combine the size specificity of cyclodextrins for guests and the transport properties of phospho-lipidic structures. The final objects could be of importance to transport or target biologically relevant molecules such as drugs using new galenic formulations. In a first step, a new family of amphiphilic CDs was prepared from a pure phospholipids (DMPE) onto cyclodextrins or methylated derivatives through a spacing arm. The afforded compounds (phospholipidyl-cyclodextrins) were fully characterized by high field NMR and high resolution mass spectrometry. The methylated derivatives were shown to self-organize in water with low CMC to form fluctuating micellar fibers retaining the inclusion capacity of the cyclodextrin cavities. The interactions of these compounds with membrane systems were investigated as black films using X-ray reflectivity and by evaluation of their detergent power towards model DMPC liposomes. Their ability to cross over the Blood Brain Barrier was evidenced by a new approach making use of novel immuno-enzymatic assays. In a second step, a new class of amphiphilic cyclodextrins was considered (peptidolipidyl-cyclodextrins). Although they are structurally similar to phospholipidyl-CDs, their preparation overcomes the tedious steps of the later and lead to a considerable versatility in terms of the number of possible molecules to be prepared. Moreover, the stability problems encountered with phospholipids are avoided. Several examples have been prepared, fully characterized and their organization properties investigated by the determination of CMC and by deuterium NMR on a pure and homogeneous mixed peptidolipidyl-CD / DMPC lamellar phase. This novel class of

Self-assembly of poly(ionic liquid) (PIL)-based amphiphilic homopolymers into vesicles and supramolecular structures with dyes and silver nanoparticles

KAUST Repository

Manojkumar, Kasina

2017-04-27

The incorporation of both hydrophilic and hydrophobic segments in homopolymers leads to their self-assembly into nanostructures in selective solvents, owing to their amphiphilic character. Here we report the RAFT polymerization of N-imidazole-3-propylmethacrylamide and the further quaternization of the resulting polymer with different alkyl bromides of a varying chain length, which afforded well-defined polymeric ionic liquids (PILs) 1-4. These PILs are characterized by the presence of both hydrophobic alkyl chains and hydrophilic ionic moieties, allowing their spontaneous self-assembly in water, forming distinct polymeric vesicles (= polymersomes) the size of which can be varied as a function of alkyl chain length. As demonstrated by the dye-encapsulation study, a particular organic-soluble PIL, 3, consisting of a dodecyl side-chain enabled the transfer of the water-soluble Rose Bengal dye, from an aqueous solution to the organic phase. In addition, polymersomes obtained from a PIL (2) featuring butyl side chains were used as templates and polymeric stabilizers of silver nanoparticles (NPs), i.e. leading to AgNP@PIL hybrids, as observed by transmission electron microscopy (TEM). It was found that the extent of functionalization of polymersomes by the Ag-based NPs varied greatly before and after the end-group removal of the PIL. Altogether, this report emphasizes the facile synthesis of amphiphilic homoPILs and their manipulation in water for dye encapsulation and for stabilization of silver NPs.

Self-assembly of poly(ionic liquid) (PIL)-based amphiphilic homopolymers into vesicles and supramolecular structures with dyes and silver nanoparticles

KAUST Repository

Manojkumar, Kasina; Mecerreyes, David; Taton, Daniel; Gnanou, Yves; Vijayakrishna, Kari

2017-01-01

The incorporation of both hydrophilic and hydrophobic segments in homopolymers leads to their self-assembly into nanostructures in selective solvents, owing to their amphiphilic character. Here we report the RAFT polymerization of N-imidazole-3-propylmethacrylamide and the further quaternization of the resulting polymer with different alkyl bromides of a varying chain length, which afforded well-defined polymeric ionic liquids (PILs) 1-4. These PILs are characterized by the presence of both hydrophobic alkyl chains and hydrophilic ionic moieties, allowing their spontaneous self-assembly in water, forming distinct polymeric vesicles (= polymersomes) the size of which can be varied as a function of alkyl chain length. As demonstrated by the dye-encapsulation study, a particular organic-soluble PIL, 3, consisting of a dodecyl side-chain enabled the transfer of the water-soluble Rose Bengal dye, from an aqueous solution to the organic phase. In addition, polymersomes obtained from a PIL (2) featuring butyl side chains were used as templates and polymeric stabilizers of silver nanoparticles (NPs), i.e. leading to AgNP@PIL hybrids, as observed by transmission electron microscopy (TEM). It was found that the extent of functionalization of polymersomes by the Ag-based NPs varied greatly before and after the end-group removal of the PIL. Altogether, this report emphasizes the facile synthesis of amphiphilic homoPILs and their manipulation in water for dye encapsulation and for stabilization of silver NPs.

Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors.

Science.gov (United States)

Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C A; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L

2018-02-01

A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large proteins, in which mechanical stress induces a coordinated movement. However, artificial molecular muscles have often relied on covalent polymer-based actuators. Here, we describe the macroscopic contractile muscle-like motion of a supramolecular system (comprising 95% water) formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor. The molecular motor first assembles into nanofibres, which further assemble into aligned bundles that make up centimetre-long strings. Irradiation induces rotary motion of the molecular motors, and propagation and accumulation of this motion lead to contraction of the fibres towards the light source. This system supports large-amplitude motion, fast response, precise control over shape, as well as weight-lifting experiments in water and air.

Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors

Science.gov (United States)

Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C. A.; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L.

2018-02-01

A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large proteins, in which mechanical stress induces a coordinated movement. However, artificial molecular muscles have often relied on covalent polymer-based actuators. Here, we describe the macroscopic contractile muscle-like motion of a supramolecular system (comprising 95% water) formed by the hierarchical self-assembly of a photoresponsive amphiphilic molecular motor. The molecular motor first assembles into nanofibres, which further assemble into aligned bundles that make up centimetre-long strings. Irradiation induces rotary motion of the molecular motors, and propagation and accumulation of this motion lead to contraction of the fibres towards the light source. This system supports large-amplitude motion, fast response, precise control over shape, as well as weight-lifting experiments in water and air.

Amphiphilic polymer based on fluoroalkyl and PEG side chains for fouling release coating

Science.gov (United States)

Cong, W. W.; Wang, K.; Yu, X. Y.; Zhang, H. Q.; Lv, Z.; Gui, T. J.

2017-12-01

Under static conditions, fouling release coating could not express good release property to marine organisms. Amphiphilic polymer with mixture of fluorinated monomer and short side group of polyethylene glycol (PEG) was synthesized. And also we studied the ability of amphiphilic polymer to influence the surface properties and how it controlled the adhesion of marine organisms to coated surfaces. By incorporating fluorinated monomer and PEG side chain into the polymer, the effect of incorporating both polar and non-polar groups on fouling-release coating could be studied. The dry surface was characterized by three-dimensional digital microscopy and scanning electron microscopy (SEM), and the morphology of the amphiphilic fouling release coating showed just like flaky petal. The amphiphilic polymer in fouling release coating tended to reconstruct in water, and the ability was examined by static contact angle, which was smaller than the PDMS (polydimethylsiloxane) fouling release coating. Also surface energy was calculated by three solvents, and surface energy of amphiphilic fouling release coating was higher than that of the PDMS fouling release coating. To understand more about its fouling release property, seawater exposure method was adopted in gulf of Qingdao port. Fewer diatoms Navicula were found in biofilm after using amphiphilic fouling release coating. In general, coating containing both PEG and fluorinated side chain possessed certain fouling release property.

Functional supramolecular polymers for biomedical applications.

Science.gov (United States)

Dong, Ruijiao; Zhou, Yongfeng; Huang, Xiaohua; Zhu, Xinyuan; Lu, Yunfeng; Shen, Jian

2015-01-21

As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular luminescence from oligofluorenol-based supramolecular polymer semiconductors.

Science.gov (United States)

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

2013-11-13

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.

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.

Amphiphilic block copolymers for biomedical applications

Science.gov (United States)

Zupancich, John Andrew

Amphiphilic block copolymer self-assembly provides a versatile means to prepare nanoscale objects in solution. Control over aggregate shape is granted through manipulation of amphiphile composition and the synthesis of well-defined polymers offers the potential to produce micelles with geometries optimized for specific applications. Currently, polymer micelles are being investigated as vehicles for the delivery of therapeutics and attempts to increase efficacy has motivated efforts to incorporate bioactive ligands and stimuli-responsive character into these structures. This thesis reports the synthesis and self-assembly of biocompatible, degradable polymeric amphiphiles. Spherical, cylindrical, and bilayered vesicle structures were generated spontaneously by the direct dispersion of poly(ethylene oxide)-b-poly(gamma-methyl-ε-caprolactone) block copolymers in water and solutions were characterized with cryogenic transmission electron microscopy (cryo-TEM). The dependence of micelle structure on diblock copolymer composition was examined through the systematic variation of the hydrophobic block molecular weight. A continuous evolution of morphology was observed with coexistence of aggregate structures occurring in windows of composition intermediate to that of pure spheres, cylinders and vesicles. A number of heterobifunctional poly(ethylene oxide) polymers were synthesized for the preparation of ligand-functionalized amphiphilic diblock copolymers. The effect of ligand conjugation on block copolymer self-assembly and micelle morphology was also examined. An RGD-containing peptide sequence was efficiently conjugated to a set of well characterized poly(ethylene oxide)-b-poly(butadiene) copolymers. The reported aggregate morphologies of peptide-functionalized polymeric amphiphiles deviated from canonical structures and the micelle clustering, cylinder fragmentation, network formation, and multilayer vesicle generation documented with cryo-TEM was attributed to

Lipophosphoramidate-based bipolar amphiphiles: their syntheses and transfection properties.

Science.gov (United States)

Berchel, Mathieu; Le Gall, Tony; Lozach, Olivier; Haelters, Jean-Pierre; Montier, Tristan; Jaffrès, Paul-Alain

2016-03-14

Six new cationic bolaamphiphiles (also called bipolar amphiphiles, bolaform amphiphiles, or bolalipids) were readily prepared by a thiol-ene click reaction that engaged a mercapto-alcohol (mercapto-ethanol or mercapto-hexanol) and a cationic based lipophosphoramidate. The cationic lipophosphoramidates contain two lipid chains that end in an alkene group and a selected cationic polar head group (trimethylammonium, dimethyl hydroxyethyl ammonium, or methylimidazolium). These compounds were formulated in water (with or without DOPE as a colipid) to produce supramolecular aggregates. These aggregates, before (i.e. bolasomes) and after (i.e. bolaplexes) mixing with plasmid DNA (pDNA) at various charge ratios, were characterized with regard to their sizes and zeta potentials. In the case of bolasomes, the suspensions were unstable since precipitation occurred after only a few hours at room temperature. On the other hand, bolaplex formulations exhibited clearly a better colloidal stability. Then, the gene delivery properties of the cationic bolasomes were investigated using two human-derived epithelial cell lines (A549 and 16HBE). Compared to the commercially available lipofection reagent (Lipofectamine), most of the cationic bolaamphiphiles were able to efficiently transfect these cells when they were formulated with DOPE in a 1 : 1 molar ratio. We report herein that bolaamphiphiles possessing a trimethylammonium or a dimethyl hydroxyethyl ammonium head group were the most efficient in terms of transfection efficiency while exhibiting no significant cytotoxicity.

Self-assembly of fibronectin mimetic peptide-amphiphile nanofibers

Science.gov (United States)

Rexeisen, Emilie Lynn

Many therapeutic strategies incorporate peptides into their designs to mimic the natural protein ligands found in vivo. A few examples are the short peptide sequences RGD and PHSRN that mimic the primary and synergy-binding domains of the extracellular matrix protein, fibronectin, which is recognized by the cell surface receptor, alpha5beta 1 integrin. Even though scaffold modification with biomimetic peptides remains one of the most promising approaches for tissue engineering, the use of these peptides in therapeutic tissue-engineered products and drug delivery systems available on the commercial market is limited because the peptides are not easily able to mimic the natural protein. The design of a peptide that can effectively target the alpha5beta1 integrin would greatly increase biomimetic scaffold therapeutic potential. A novel peptide containing both the RGD primary binding domain and PHSRN synergy-binding domain for fibronectin joined with the appropriate linker should bind alpha 5beta1 integrin more efficiently and lead to greater cell adhesion over RGD alone. Several fibronectin mimetic peptides were designed and coupled to dialkyl hydrocarbon tails to make peptide-amphiphiles. The peptides contained different linkers connecting the two binding domains and different spacers separating the hydrophobic tails from the hydrophilic headgroups. The peptide-amphiphiles were deposited on mica substrates using the Langmuir-Blodgett technique. Langmuir isotherms indicated that the peptide-amphiphiles that contained higher numbers of serine residues formed a more tightly packed monolayer, but the increased number of serines also made transferring the amphiphiles to the mica substrate more difficult. Atomic force microscopy (AFM) images of the bilayers showed that the headgroups might be bent, forming small divots in the surface. These divots may help expose the PHSRN synergy-binding domain. Parallel studies undertaken by fellow group members showed that human

Strong and Reversible Monovalent Supramolecular Protein Immobilization

NARCIS (Netherlands)

Young, Jacqui F.; Nguyen, Hoang D.; Yang, Lanti; Huskens, Jurriaan; Jonkheijm, Pascal; Brunsveld, Luc

2010-01-01

Proteins with an iron clasp: Site-selective incorporation of a ferrocene molecule into a protein allows for easy, strong, and reversible supramolecular protein immobilization through a selective monovalent interaction of the ferrocene with a cucurbit[7]uril immobilized on a gold surface. The

(CryoTransmission Electron Microscopy of Phospholipid Model Membranes Interacting with Amphiphilic and Polyphilic Molecules

Directory of Open Access Journals (Sweden)

Annette Meister

2017-10-01

Full Text Available Lipid membranes can incorporate amphiphilic or polyphilic molecules leading to specific functionalities and to adaptable properties of the lipid bilayer host. The insertion of guest molecules into membranes frequently induces changes in the shape of the lipid matrix that can be visualized by transmission electron microscopy (TEM techniques. Here, we review the use of stained and vitrified specimens in (cryoTEM to characterize the morphology of amphiphilic and polyphilic molecules upon insertion into phospholipid model membranes. Special emphasis is placed on the impact of novel synthetic amphiphilic and polyphilic bolalipids and polymers on membrane integrity and shape stability.

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

Flat-on ambipolar triphenylamine/C60 nano-stacks formed from the self-organization of a pyramid-sphere-shaped amphiphile.

Science.gov (United States)

Liang, Wei-Wei; Huang, Chi-Feng; Wu, Kuan-Yi; Wu, San-Lien; Chang, Shu-Ting; Cheng, Yen-Ju; Wang, Chien-Lung

2016-04-21

A giant amphiphile, which is constructed with an amorphous nano-pyramid (triphenylamine, TPA) and a crystalline nano-sphere (C 60 ), was synthesized. Structural characterization indicates that this pyramid-sphere-shaped amphiphile ( TPA-C 60 ) forms a solvent-induced ordered phase, in which the two constituent units self-assemble into alternating stacks of two-dimensional (2D) TPA and C 60 nano-sheets. Due to the complexity of the molecular structure and the amorphous nature of the nano-pyramid, phase formation was driven by intermolecular C 60 -C 60 interactions and the ordered phase could not be reformed from the TPA-C 60 melt. Oriented crystal arrays of TPA-C 60 , which contain flat-on TPA/C 60 nano-stacks, can be obtained via a PDMS-assisted crystallization (PAC) technique. The flat-on dual-channel supramolecular structure of TPA-C 60 delivered ambipolar and balanced charge-transport characteristics with an average μ e of 2.11 × 10 -4 cm 2 V -1 s -1 and μ h of 3.37 × 10 -4 cm 2 V -1 s -1 . The anisotropic charge-transport ability of the pyramid-sphere-shaped amphiphile was further understood based on the lattice structure and the lattice orientation of TPA-C 60 revealed from electron diffraction analyses.

Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers

NARCIS (Netherlands)

Schaeffer, Gaël; Buhler, Eric; Candau, Sauveur Jean; Lehn, Jean-Marie

2013-01-01

Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (“double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in

An Amylase-Responsive Bolaform Supra-Amphiphile.

Science.gov (United States)

Kang, Yuetong; Cai, Zhengguo; Tang, Xiaoyan; Liu, Kai; Wang, Guangtong; Zhang, Xi

2016-02-01

An amylase-responsive bolaform supra-amphiphile was constructed by the complexation between β-cyclodextrin and a bolaform covalent amphiphile on the basis of host-guest interaction. The bolaform covalent amphiphile could self-assemble in solution, forming sheet-like aggregates and displaying weak fluorescence because of aggregation-induced quenching. The addition of β-cyclodextrin led to the formation of the bolaform supra-amphiphile, prohibiting the aggregation of the bolaform covalent amphiphile and accompanying with the significant recovery of fluorescence. Upon the addition of α-amylase, with the degradation β-cyclodextrin, the fluorescence of the supra-amphiphile would quench gradually and significantly, and the quenching rate linearly correlated to the concentration of α-amylase. This study enriches the field of supra-amphiphiles on the basis of noncovalent interactions, and moreover, it may provide a facile way to estimate the activity of α-amylase.

Supramolecular "Trojan Horse" for Nuclear Delivery of Dual Anticancer Drugs.

Science.gov (United States)

Cai, Yanbin; Shen, Haosheng; Zhan, Jie; Lin, Mingliang; Dai, Liuhan; Ren, Chunhua; Shi, Yang; Liu, Jianfeng; Gao, Jie; Yang, Zhimou

2017-03-01

Nuclear delivery and accumulation are very important for many anticancer drugs that interact with DNA or its associated enzymes in the nucleus. However, it is very difficult for neutrally and negatively charged anticancer drugs such as 10-hydroxycamptothecine (HCPT). Here we report a simple strategy to construct supramolecular nanomedicines for nuclear delivery of dual synergistic anticancer drugs. Our strategy utilizes the coassembly of a negatively charged HCPT-peptide amphiphile and the positively charged cisplatin. The resulting nanomaterials behave as the "Trojan Horse" that transported soldiers (anticancer drugs) across the walls of the castle (cell and nucleus membranes). Therefore, they show improved inhibition capacity to cancer cells including the drug resistant cancer cell and promote the synergistic tumor suppression property in vivo. We envision that our strategy of constructing nanomaterials by metal chelation would offer new opportunities to develop nanomedicines for combination chemotherapy.

Graphene oxide-enhanced sol-gel transition sensitivity and drug release performance of an amphiphilic copolymer-based nanocomposite

Science.gov (United States)

Hu, Huawen; Wang, Xiaowen; Lee, Ka I; Ma, Kaikai; Hu, Hong; Xin, John H.

2016-01-01

We report the fabrication of a highly sensitive amphiphilic copolymer-based nanocomposite incorporating with graphene oxide (GO), which exhibited a low-intensity UV light-triggered sol-gel transition. Non-cytotoxicity was observed for the composite gels after the GO incorporation. Of particular interest were the microchannels that were formed spontaneously within the GO-incorporated UV-gel, which expedited sustained drug release. Therefore, the present highly UV-sensitive, non-cytotoxic amphiphilic copolymer-based composites is expected to provide enhanced photothermal therapy and chemotherapy by means of GO’s unique photothermal properties, as well as through efficient passive targeting resulting from the sol-gel transition characteristic of the copolymer-based system with improved sensitivity, which thus promises the enhanced treatment of patients with cancer and other diseases. PMID:27539298

Development of a Room Temperature SAW Methane Gas Sensor Incorporating a Supramolecular Cryptophane A Coating

Directory of Open Access Journals (Sweden)

Wen Wang

2016-01-01

Full Text Available A new room temperature supra-molecular cryptophane A (CrypA-coated surface acoustic wave (SAW sensor for sensing methane gas is presented. The sensor is composed of differential resonator-oscillators, a supra-molecular CrypA coated along the acoustic propagation path, and a frequency signal acquisition module (FSAM. A two-port SAW resonator configuration with low insertion loss, single resonation mode, and high quality factor was designed on a temperature-compensated ST-X quartz substrate, and as the feedback of the differntial oscillators. Prior to development, the coupling of modes (COM simulation was conducted to predict the device performance. The supramolecular CrypA was synthesized from vanillyl alcohol using a double trimerisation method and deposited onto the SAW propagation path of the sensing resonators via different film deposition methods. Experiential results indicate the CrypA-coated sensor made using a dropping method exhibits higher sensor response compared to the unit prepared by the spinning approach because of the obviously larger surface roughness. Fast response and excellent repeatability were observed in gas sensing experiments, and the estimated detection limit and measured sensitivity are ~0.05% and ~204 Hz/%, respectively.

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

Tailoring nanostructure and bioactivity of 3D printable hydrogels with self-assemble Peptides Amphiphile (PA) for promoting bile duct formation.

Science.gov (United States)

Yan, Ming; Lewis, Phillip L; Shah, Ramille N

2018-05-31

3D-printing has expanded our ability to produce reproducible and more complex scaffold architectures for tissue engineering applications. In order to enhance the biological response within these 3D printed scaffolds incorporating nanostructural features and/or specific biological signaling may be an effective means to optimize tissue regeneration. Peptides Amphiphiles (PAs) are a versatile supramolecular biomaterial with tailorable nanostructural and biochemical features. PAs are widely used in tissue engineering applications such as angiogenesis, neurogenesis, and bone regeneration. Thus, the addition of PAs is a potential solution that can greatly expand the utility of 3D bio-printing hydrogels in the field of regenerative medicine. In this paper, we firstly developed a 3D printable thiolated-gelatin bioink supplemented with PAs to tailor the bioactivity and nanostructure which allows for the incorporation of cells. The bioink can be printed at 4 °C and stabilized to last a long time (>1 month) in culture at 37 °C by via a dual secondary cross-linking strategy using calcium ions and homobifunctional maleiminde-poly (ethylene glycol). Rheological properties of inks were characterized and were suitable for printing multi-layered structures. We additionally demonstrated enhanced functionality of ink formulations by utilizing a laminin-mimetic IKVAV-based PA system within a 3D-printable ink containing cholangiocytes. Viability and functional staining showed that the IKVAV PA nanofibers stimulated cholangioctyes to form functional tubular structures, which was not observed in other ink formulations. . © 2018 IOP Publishing Ltd.

Incorporation of nano-clay saponite layers in the organo-clay hybrid films using anionic amphiphile stearic acid by Langmuir–Blodgett technique

Energy Technology Data Exchange (ETDEWEB)

Hussain, Syed Arshad, E-mail: sa_h153@hotmail.com [Department of Physics, Tripura University, Suryamaninagar-799022 (India); Chakraborty, S.; Bhattacharjee, D. [Department of Physics, Tripura University, Suryamaninagar-799022 (India); Schoonheydt, R.A. [Centres for Surface Chemistry and Catalysis, K.U. Leuven, Kasteelpark Arenberg 23, 3001 Leuven (Belgium)

2013-06-01

In general cationic amphiphiles are used to prepare organo-clay hybrid film in Langmuir–Blodgett (LB) technique. In this present communication we demonstrated a unique technique to prepare the organo–clay hybrid films using an anionic amphiphile. The T–O–T type clay saponite was incorporated onto a floating stearic acid monolayer via a divalent cation Mg{sup 2+}. Salt MgCl{sub 2} was mixed along with the clay dispersion in the LB trough and amphiphile solution was spread onto the subphase in order to make the organo-clay hybrid films. It was observed that salt (MgCl{sub 2}) concentration on the subphase affects the organization of nano-dimensional clay platelet (saponite) in organo-clay hybrid films at air–water interface as well as in LB films. Noticeable changes in area per molecule and shape of the isotherms were observed and measured at subphases with different salt concentrations. Infrared reflection absorption spectroscopy studies reveal that only an in-plane (996 cm{sup −1}) vibration of ν (Si-O) band occurred when the salt concentration was 10 mM. However, both in-plane (996 cm{sup −1}) and out-of-plane (1063 cm{sup −1}) vibrations of the ν (Si-O) band of saponite occurred when the subphase salt concentration was 100 mM. Also the out-of-plane vibration of ν (OH) of saponite was prominent at higher salt concentration. This is because at lower salt concentration clay sheets remain flat on the surface whereas; at higher MgCl{sub 2} concentration they aggregated and form stacks of saponite layers. Also they may be slightly tilted with a very small tilt angle at higher salt concentration making a favorable condition for both in-plane and out-of-plane vibrations of ν (Si-O) in the hybrid films. Observed decrease in starting area per molecule in the pressure area isotherm measured at higher salt concentration also supports the tilting of clay layers at air–clay dispersion interface. Attentuated total reflectance Fourier transform infrared

Biomimetic surface coatings from modular amphiphilic proteins

Science.gov (United States)

Harden, James; Wan, Fan; Fischer, Stephen; Dick, Scott

2010-03-01

Recombinant DNA methods have been used to develop a library of diblock protein polymers for creating designer biofunctional interfaces. These proteins are composed of a surface-active, amphiphilic block joined to a disordered, water soluble block with an end terminal bioactive domain. The amphiphilic block has a strong affinity for many synthetic polymer surfaces, providing a facile means of imparting biological functionality to otherwise bio-neutral materials through physical self-assembly. We have incorporated a series of bioactive end domains into this diblock motif, including sequences that encode specific cell binding and signaling functions of extracellular matrix constituents (e.g. RGD and YIGSR). In this talk, we show that these diblock constructs self-assemble into biofunctional surface coatings on several model synthetic polymer materials. We demonstrate that surface adsorption of the proteins has minimal impacts on the presentation of the bioactive domains in the soluble block, and through the use of microscopic and cell proliferation assays, we show that the resulting biofunctional interfaces are capable of inducing appropriate cellular responses in a variety of human cell types.

Supramolecular assembly/reassembly processes: molecular motors and dynamers operating at surfaces.

Science.gov (United States)

Ciesielski, Artur; Samorì, Paolo

2011-04-01

Among the many significant advances within the field of supramolecular chemistry over the past decades, the development of the so-called "dynamers" features a direct relevance to materials science. Defined as "combinatorial dynamic polymers", dynamers are constitutional dynamic systems and materials resulting from the application of the principles of supramolecular chemistry to polymer science. Like supramolecular materials in general, dynamers are reversible dynamic multifunctional architectures, capable of modifying their constitution by exchanging, recombining, incorporating components. They may exhibit a variety of novel properties and behave as adaptive materials. In this review we focus on the design of responsive switchable monolayers, i.e. monolayers capable to undergo significant changes in their physical or chemical properties as a result of external stimuli. Scanning tunneling microscopy studies provide direct evidence with a sub-nanometre resolution, on the formation and dynamic response of these self-assembled systems featuring controlled geometries and properties.

Revealing the Supramolecular Nature of Side-Chain Terpyridine-Functionalized Polymer Networks

Directory of Open Access Journals (Sweden)

Jérémy Brassinne

2015-01-01

Full Text Available Nowadays, finely controlling the mechanical properties of polymeric materials is possible by incorporating supramolecular motifs into their architecture. In this context, the synthesis of a side-chain terpyridine-functionalized poly(2-(dimethylaminoethyl methacrylate is reported via reversible addition-fragmentation chain transfer polymerization. By addition of transition metal ions, concentrated aqueous solutions of this polymer turn into metallo-supramolecular hydrogels whose dynamic mechanical properties are investigated by rotational rheometry. Hence, the possibility for the material to relax mechanical constrains via dissociation of transient cross-links is brought into light. In addition, the complex phenomena occurring under large oscillatory shear are interpreted in the context of transient networks.

Fluctuations and structure of amphiphilic films; Fluctuations et structure de films d`amphiphiles

Energy Technology Data Exchange (ETDEWEB)

Gourier, CH

1996-07-01

This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

Combination of SEDDS and Preactivated Thiomer Technology: Incorporation of a Preactivated Thiolated Amphiphilic Polymer into Self-Emulsifying Delivery Systems.

Science.gov (United States)

Hetényi, Gergely; Griesser, Janine; Nardin, Isabelle; Bernkop-Schnürch, Andreas

2017-06-01

The aim of the study was to create novel mucoadhesive drug delivery systems by incorporating amphiphilic hydrophobically modified, thiolated and preactivated polymers (preactivated thiomers) into self-emulsifying drug delivery systems (SEDDS). L-Cysteine methyl ester was covalently attached to the polymeric backbone of Pemulen TR-2 and preactivated using 2-mercaptonicotinic acid (2-MNA). These thiomers were incorporated in a concentration of 0.3% (w/v) into SEDDS. The size distribution and the zeta potential of the emulsions were evaluated by dynamic light scattering. Mucoadhesive properties of thiomers-SEDDS spiked with FDA (fluorescein diacetate) were examined utilizing rheological measurement, permeation studies and in vitro residence time study on porcine mucosa. Cell viability tests were additionally performed. 734 ± 58 μmol L-Cysteine methyl ester and 562 ± 71 μmol 2-MNA could be attached per gram polymer of Pemulen TR-2. Emulsions exhibited a droplet size range between 180 and 270 nm. Blank SEDDS possessed a zeta potential value between -5.7 and -8.6 mV, whereas thiomers-SEDDS between -14.6 and -17.2 mV. Viscous modulus of thiomer and preactivated thiomer containing SEDDS-mucus mixture was 8-fold and 11-fold increased in comparison to reference. The amount of FDA permeated the mucus layer was 2-fold lower in case of thiomers-SEDDS compared to blank SEDDS. A prolonged residence time was observed for thiomers-SEDDS over 45 min. During cell viability studies no severe toxic effects were detected. The novel developed SEDDS with incorporated thiomers might be a promising tool for mucoadhesive oral drug delivery.

Compartmentalization Technologies via Self-Assembly and Cross-Linking of Amphiphilic Random Block Copolymers in Water.

Science.gov (United States)

Matsumoto, Mayuko; Terashima, Takaya; Matsumoto, Kazuma; Takenaka, Mikihito; Sawamoto, Mitsuo

2017-05-31

Orthogonal self-assembly and intramolecular cross-linking of amphiphilic random block copolymers in water afforded an approach to tailor-make well-defined compartments and domains in single polymer chains and nanoaggregates. For a double compartment single-chain polymer, an amphiphilic random block copolymer bearing hydrophilic poly(ethylene glycol) (PEG) and hydrophobic dodecyl, benzyl, and olefin pendants was synthesized by living radical polymerization (LRP) and postfunctionalization; the dodecyl and benzyl units were incorporated into the different block segments, whereas PEG pendants were statistically attached along a chain. The copolymer self-folded via the orthogonal self-assembly of hydrophobic dodecyl and benzyl pendants in water, followed by intramolecular cross-linking, to form a single-chain polymer carrying double yet distinct hydrophobic nanocompartments. A single-chain cross-linked polymer with a chlorine terminal served as a globular macroinitiator for LRP to provide an amphiphilic tadpole macromolecule comprising a hydrophilic nanoparticle and a hydrophobic polymer tail; the tadpole thus self-assembled into multicompartment aggregates in water.

H-shaped supra-amphiphiles based on a dynamic covalent bond.

Science.gov (United States)

Wang, Guangtong; Wang, Chao; Wang, Zhiqiang; Zhang, Xi

2012-10-16

The imine bond, a kind of dynamic covalent bond, is used to bind two bolaform amphiphiles together with spacers, yielding H-shaped supra-amphiphiles. Micellar aggregates formed by the self-assembly of the H-shaped supra-amphiphiles are observed. When pH is tuned down from basic to slightly acidic, the benzoic imine bond can be hydrolyzed, leading to the dissociation of H-shaped supra-amphiphiles. Moreover, H-shaped supra-amphiphiles have a lower critical micelle concentration than their building blocks, which is very helpful in enhancing the stability of the benzoic imine bond being hydrolyzed by acid. The surface tension isotherms of the H-shaped supra-amphiphiles with different spacers indicate their twisty conformation at a gas-water interface. The study of H-shaped supra-amphiphiles can enrich the family of amphiphiles, and moreover, the pH-responsiveness may make them apply to controlled or targetable drug delivery in a biological environment.

Vaccine Adjuvant Incorporation Strategy Dictates Peptide Amphiphile Micelle Immunostimulatory Capacity.

Science.gov (United States)

Zhang, Rui; Kramer, Jake S; Smith, Josiah D; Allen, Brittany N; Leeper, Caitlin N; Li, Xiaolei; Morton, Logan D; Gallazzi, Fabio; Ulery, Bret D

2018-06-01

Current vaccine research has shifted from traditional vaccines (i.e., whole-killed or live-attenuated) to subunit vaccines (i.e., protein, peptide, or DNA) as the latter is much safer due to delivering only the bioactive components necessary to produce a desirable immune response. Unfortunately, subunit vaccines are very weak immunogens requiring delivery vehicles and the addition of immunostimulatory molecules termed adjuvants to convey protective immunity. An interesting type of delivery vehicle is peptide amphiphile micelles (PAMs), unique biomaterials where the vaccine is part of the nanomaterial itself. Due to the modularity of PAMs, they can be readily modified to deliver both vaccine antigens and adjuvants within a singular construct. Through the co-delivery of a model antigenic epitope (Ovalbumin 319-340 -OVA BT ) and a known molecular adjuvant (e.g., 2,3-dipalmitoyl-S-glyceryl cysteine-Pam 2 C), greater insight into the mechanisms by which PAMs can exert immunostimulatory effects was gained. It was found that specific combinations of antigen and adjuvant can significantly alter vaccine immunogenicity both in vitro and in vivo. These results inform fundamental design rules that can be leveraged to fabricate optimal PAM-based vaccine formulations for future disease-specific applications. Graphical Abstract.

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.

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.

Disassembly Control of Saccharide-Based Amphiphiles Driven by Electrostatic Repulsion.

Science.gov (United States)

Yamada, Taihei; Kokado, Kenta; Sada, Kazuki

2017-03-14

According to the design of disassembly using electrostatic repulsion, novel amphiphiles consisting of a lipophilic ion part and a hydrophilic saccharide part were synthesized via the facile copper-catalyzed click reaction, and their molecular assemblies in water and chloroform were studied. The amphiphiles exhibited a molecular orientation opposite to that of the conventional amphiphiles in each case. ζ Potential measurements indicated that the lipophilic ion part is exposed outside in chloroform. The size of a solvophobic part in the amphiphiles dominates the size of an assembling structure; that is, in water, these amphiphiles tethering different lengths of the saccharide part exhibited almost identical assembling size, whereas in chloroform, the size depends on the length of the saccharide part in the amphiphiles.

Computational Amphiphilic Materials for Drug Delivery

Directory of Open Access Journals (Sweden)

Naresh eThota

2015-10-01

Full Text Available Amphiphilic materials can assemble into a wide variety of morphologies and have emerged as a novel class of candidates for drug delivery. Along with a large number of experiments reported, computational studies have been also conducted in this field. At an atomistic/molecular level, computations can facilitate quantitative understanding of experimental observations and secure fundamental interpretation of underlying phenomena. This review summarizes the recent computational efforts on amphiphilic copolymers and peptides for drug delivery. Atom-resolution and time-resolved insights are provided from bottom-up to microscopically elucidate the mechanisms of drug loading/release, which are indispensable in the rational screening and design of new amphiphiles for high-efficacy drug delivery.

Rheology of Supramolecular Polymers

DEFF Research Database (Denmark)

Shabbir, Aamir

Supramolecular polymers are a broad class of materials that include all polymerscapable of associating via secondary interactions. These materials represent an emerging class of systems with superior versatility compared to classical polymers with applications in food stuff, coatings, cost...... efficient processes or biomedical areas. Design and development of supramolecular polymers using ionic, hydrogen bonding or transition metal complexes with tailored properties requires deep understanding of dynamics both in linear and non-linear deformations. While linear rheology is important to understand...... the dynamics under equilibrium conditions, extensional rheology is relevant during the processing or in the usage of polymers utilizing supramolecular associations for example, acrylic based pressure sensitive adhesives are subjected to extensional deformations during the peeling where strain hardening...

Tandem Facial Amphiphiles for Membrane Protein Stabilization

DEFF Research Database (Denmark)

Chae, Pil Seok; Gotfryd, Kamil; Pacyna, Jennifer

2010-01-01

We describe a new type of synthetic amphiphile that is intended to support biochemical characterization of intrinsic membrane proteins. Members of this new family displayed favorable behavior with four of five membrane proteins tested, and these amphiphiles formed relatively small micelles....

Combining supramolecular chemistry with biology

NARCIS (Netherlands)

Uhlenheuer, D.A.; Petkau - Milroy, K.; Brunsveld, L.

2010-01-01

Supramolecular chemistry has primarily found its inspiration in biological molecules, such as proteins and lipids, and their interactions. Currently the supramolecular assembly of designed compounds can be controlled to great extent. This provides the opportunity to combine these synthetic

Metallo-supramolecular block copolymer micelles

NARCIS (Netherlands)

Gohy, J.M.W.

2009-01-01

Supramolecular copolymers have become of increasing interest in recent years in the search for new materials with tunable properties. In particular, metallo-supramolecular block copolymers in which metal-ligand complexes are introduced in block copolymer architectures, have known important progress,

Supramolecular architectures in layer-by-layer films of single-walled carbon nanotubes, chitosan and cobalt (II) phthalocyanine

International Nuclear Information System (INIS)

Sousa Luz, Roberto A. de; Martins, Marccus Victor A.; Magalhaes, Janildo L.; Siqueira, Jose R.; Zucolotto, Valtencir; Oliveira, Osvaldo N.; Crespilho, Frank N.; Cantanhede da Silva, Welter

2011-01-01

Highlights: → Platforms were assembled from cobalt phthalocyanine, chitosan and carbon nanotubes. → Supramolecular organization of multilayer films was investigated. → Increase of the supramolecular charge transfer after carbon nanotube incorporation. → Functional modulation based on constitutional dynamic chemistry was achieved. - Abstract: The building of supramolecular structures in nanostructured films has been exploited for a number of applications, with the film properties being controlled at the molecular level. In this study, we report on the layer-by-layer (LbL) films combining cobalt (II) tetrasulfonated phthalocyanine (CoTsPc), chitosan (Chit) and single-walled carbon nanotubes (SWCNTs) in two architectures, {Chit/CoTsPc} n and {Chit-SWCNTs/CoTsPc} n (n = 1-10). The physicochemical properties of the films were evaluated and the multilayer formation was monitored with microgravimetry measurements using a quartz microbalance crystal and an electrochemical technique. According to atomic force microscopy (AFM) results, the incorporation of SWCNTs caused the films to be thicker, with a thickness ca. 3 fold that of a 2-bilayer LbL film with no SWCNTs. Cyclic voltammetry revealed a quasi-reversible, one electron process with E 1/2 at -0.65 V (vs SCE) and an irreversible oxidation process at 0.80 V in a physiological medium for both systems, which can be attributed to [CoTsPc(I)] 5- /[CoTsPc(II)] 4- and CoTsPc(II) to CoTsPc(III), respectively. The {Chit-SWCNTs/CoTsPc} 5 multilayer film exhibited an increased faradaic current, probably associated with the supramolecular charge transfer interaction between cobalt phthalocyanine and SWCNTs. The results demonstrate that an intimate contact at the supramolecular level between functional SWCNTs immobilized into biocompatible chitosan polymer and CoTsPc improves the electron flow from CoTsPc redox sites to the electrode surface.

Fluctuations and structure of amphiphilic films

International Nuclear Information System (INIS)

Gourier, CH.

1996-01-01

This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

Main-chain supramolecular block copolymers.

Science.gov (United States)

Yang, Si Kyung; Ambade, Ashootosh V; Weck, Marcus

2011-01-01

Block copolymers are key building blocks for a variety of applications ranging from electronic devices to drug delivery. The material properties of block copolymers can be tuned and potentially improved by introducing noncovalent interactions in place of covalent linkages between polymeric blocks resulting in the formation of supramolecular block copolymers. Such materials combine the microphase separation behavior inherent to block copolymers with the responsiveness of supramolecular materials thereby affording dynamic and reversible materials. This tutorial review covers recent advances in main-chain supramolecular block copolymers and describes the design principles, synthetic approaches, advantages, and potential applications.

Structural aspects, thermal behavior, and stability of a self-assembled supramolecular polymer derived from flunixin-meglumine supramolecular adducts

Energy Technology Data Exchange (ETDEWEB)

Cassimiro, Douglas L.; Kobelnik, Marcelo [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil); Ribeiro, Clovis A., E-mail: ribeiroc@iq.unesp.br [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil); Crespi, Marisa S.; Boralle, Nivaldo [Institute of Chemistry, Paulista State University, Av. Prof. Francisco Degni, s/n, 14800-900 Araraquara, Sao Paulo (Brazil)

2012-02-10

Highlights: Black-Right-Pointing-Pointer The thermal behavior of flunixin-meglumine, a potent NSAID, was investigated. Black-Right-Pointing-Pointer This supramolecular adduct self-assembled resulting in a polymer-like material. Black-Right-Pointing-Pointer The supramolecular polymer showed a high molecular weight around 290 {+-} 88 MDa. Black-Right-Pointing-Pointer NMR and FT-IR showed that hydrogen bonding can be responsible for the self-assembly. Black-Right-Pointing-Pointer The stability of the supramolecular polymer was also studied and presented here. - Abstract: Flunixin-meglumine, a potent non-steroidal anti-inflammatory drug (NSAID) and a cyclo-oxygenase inhibitor for Veterinary use, is a hydrogen-bonded supramolecular adduct. Two monotropically related crystalline modifications (Forms I and II) were observed for a flunixin-meglumine sample. During the melt of form I, flunixin-meglumine adducts self-assembled by hydrogen bonds involving the hydroxyl groups from meglumine, resulting in an amorphous rigid glassy supramolecular polymer, which showed a high molecular weight around 290 {+-} 88 MDa and a glass transition around 49.5 Degree-Sign C. Both the adduct and the resulting supramolecular polymer were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance spectroscopy (NMR), Fourier transform-infrared spectroscopy (FT-IR), and weight-average molecular weight determination by light scattering. The chemical stability and morphological changes of the depolymerization process were also investigated for the supramolecular polymer, by DSC and scanning electron microscopy (SEM), respectively.

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

Freezing-induced self-assembly of amphiphilic molecules

Science.gov (United States)

Albouy, P. A.; Deville, S.; Fulkar, A.; Hakouk, K.; Impéror-Clerc, M.; Klotz, M.; Liu, Q.; Marcellini, M.; Perez, J.

The self-assembly of amphiphilic molecules usually takes place in a liquid phase, near room temperature. Here, using small angle X-ray scattering (SAXS) experiments performed in real time, we show that freezing of aqueous solutions of copolymer amphiphilic molecules can induce self-assembly below 0{\\deg}C.

Nanoparticles Embedded in Amphiphilic Membranes for Carbon Dioxide Separation and Dehumidification.

Science.gov (United States)

Yong, Wai Fen; Ho, Yan Xun; Chung, Tai-Shung

2017-10-23

Polymers containing ethylene oxide (EO) groups have gained significant interest as the EO groups have favorable interactions with polar molecules such as H 2 O, quadrupolar molecules such as CO 2 , and metal ions. However, the main challenges of poly(ethylene oxide) (PEO) membranes are their weak mechanical properties and high crystallinity nature. The amphiphilic copolymer made from PEO terephthalate and poly(butylene terephthalate) (PEOT/PBT) comprises both hydrophilic and hydrophobic segments. The hydrophilic PEOT segment is thermosensitive, which facilities gas transports whereas the hydrophobic PBT segment is rigid, which provides mechanical robustness. This work demonstrates a new strategy to design amphiphilic mixed matrix membranes (MMMs) by incorporating zeolitic imidazolate framework, ZIF-71, into the PEOT/PBT copolymer. The resultant membrane shows an enhanced CO 2 permeability with an ideal CO 2 /N 2 selectivity surpassing the original PEOT/PBT and Robeson's Upper bound line. The nanoparticles-embedded amphiphilic membranes exhibit characteristics of high transparency and mechanical robustness. Mechanically strong composite hollow fiber membranes consisting of PEOT/PBT/ZIF-71 as the selective layer were also prepared. The resultant hollow fibers possess an excellent CO 2 permeance of 131 GPU (gas permeation units), CO 2 /N 2 selectivity of 52.6, H 2 O permeance of 9300 GPU and H 2 O/N 2 selectivity of 3700, showing great potential for industrial CO 2 capture and dehumidification. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of the preparation route on the supramolecular organization of lipids in a vesicular system

DEFF Research Database (Denmark)

Elizondo, Elisa; Larsen, Jannik; Hatzakis, Nikos

2012-01-01

A confocal fluorescence microscopy-based assay was used for studying the influence of the preparation route on the supramolecular organization of lipids in a vesicular system. In this work, vesicles composed of cholesterol and CTAB (1/1 mol %) or cholesterol and DOPC (2/8 mol %) and incorporating...

Revealing Amphiphilic Nanodornains of Anti-Biofouling Polymer Coatings

Energy Technology Data Exchange (ETDEWEB)

Amadei, CA; Yang, R; Chiesa, M; Gleason, KK; Santos, S

2014-04-09

Undesired bacterial adhesion and biofilm formation on wetted surfaces leads to significant economic and environmental costs in various industries. Amphiphilic coatings with molecular hydrophilic and hydrophobic patches can mitigate such biofouling effectively in an environmentally friendly manner. The coatings are synthesized by copolymerizing (Hydroxyethyl)methacrylate and perfluorodecylacrylate via initiated chemical vapor deposition (iCVD). In previous studies, the size of the patches was estimated to be similar to 1.4-1.75 nm by fitting protein adsorption data to a theoretical model. However, no direct observations of the molecular heterogeneity exist and therefore the origin of the fouling resistance of amphiphilic coatings remains unclear. Here, the amphiphilic nature is investigated by amplitude modulation atomic force microscopy (AM-AFM). High-resolution images obtained by penetrating and oscillating the AFM tip under the naturally present water layer with sub-nanometer amplitudes reveal, for the first time, the existence of amphiphilic nanodomains (1-2 nm(2)). Compositional heterogeneity at the nanoscale is further corroborated by a statistical analysis on the data obtained with dynamic AM-AFM force spectroscopy. Variations in the long range attractive forces, responsible for water affinity, are also identified. These nanoscopic results on the polymers wettability are also confirmed by contact angle measurements (i.e., static and dynamic). The unprecedented ability to visualize the amphiphilic nanodomains as well as sub-nanometer crystalline structures provides strong evidence for the existence of previously postulated nanostructures, and sheds light on the underlying antifouling mechanism of amphiphilic chemistry.

The use of supramolecular chemistry in dye delivery systems

International Nuclear Information System (INIS)

Merckel, Daniel Andrew Sturton

2002-01-01

This thesis reports an investigation into supramolecular recognition of the sulfate/ sulfonate oxoanionic group, a moiety present in the majority of reactive dyes. In the first section the problems associated with the use of reactive dyes in dyeing cotton fabrics together with a literature review of supramolecular approaches to anion recognition are discussed. Drawing on the current literature concerning anion recognition (in particular the recognition of phosphates), the main body of the thesis concerns the design and synthesis of several series ofC-shaped (tweezer) and tripodal potential sulfate/ sulfonate receptors. These receptors incorporate the H-bond donor groups guanidine and thiourea and to a lesser extent urea and amide functionalities. In addition the behaviour of potential tweezer-like receptor molecules based on s-triazine (derived from cyanuric chloride) has also been investigated. The sulfate/ sulfonate and related phosphonate association properties of these potential receptors have been studied. Particular emphasis has been placed on the solid-state supramolecular structures formed by these complexes as determined by single crystal X-ray structural studies, and several novel and revealing examples have been analysed in detail. NMR titration binding studies have also been undertaken in order to investigate the complexation behaviour of several receptors with ''model dye'' phosphonates and sulfonates in solution. In addition a number of single crystal X-ray crystallographic studies were undertaken for other members of the Grossel research group during the course of this work, and the results of these structural studies are also reported. (author)

The Rheological Properties of Lipid Monolayers Modulate the Incorporation of l-Ascorbic Acid Alkyl Esters.

Science.gov (United States)

Díaz, Yenisleidy de Las Mercedes Zulueta; Mottola, Milagro; Vico, Raquel V; Wilke, Natalia; Fanani, María Laura

2016-01-19

In this work, we tested the hypothesis that the incorporation of amphiphilic drugs into lipid membranes may be regulated by their rheological properties. For this purpose, two members of the l-ascorbic acid alkyl esters family (ASCn) were selected, ASC16 and ASC14, which have different rheological properties when organized at the air/water interface. They are lipophilic forms of vitamin C used in topical pharmacological preparations. The effect of the phase state of the host lipid membranes on ASCn incorporation was explored using Langmuir monolayers. Films of pure lipids with known phase states have been selected, showing liquid-expanded, liquid-condensed, and solid phases as well as pure cholesterol films in liquid-ordered state. We also tested ternary and quaternary mixed films that mimic the properties of cholesterol containing membranes and of the stratum corneum. The compressibility and shear properties of those monolayers were assessed in order to define its phase character. We found that the length of the acyl chain of the ASCn compounds induces differential changes in the rheological properties of the host membrane and subtly regulates the kinetics and extent of the penetration process. The capacity for ASCn uptake was found to depend on the phase state of the host film. The increase in surface pressure resultant after amphiphile incorporation appears to be a function of the capacity of the host membrane to incorporate such amphiphile as well as the rheological response of the film. Hence, monolayers that show a solid phase state responded with a larger surface pressure increase to the incorporation of a comparable amount of amphiphile than liquid-expanded ones. The cholesterol-containing films, including the mixture that mimics stratum corneum, allowed a very scarce ASCn uptake independently of the membrane diffusional properties. This suggests an important contribution of Cho on the maintenance of the barrier function of stratum corneum.

Investigation on the ion pair amphiphiles and their in vitro release of amantadine drug based on PLGA–PEG–PLGA gel

International Nuclear Information System (INIS)

Yang, Xiaoxia; Ji, Xiaoqing; Shi, Chunhuan; Liu, Jing; Wang, Haiyang; Luan, Yuxia

2014-01-01

The amantadine drug and oleic acid surfactant are used to form amantadine-based ion pair amphiphiles based on proton transfer reaction between the drug and the surfactant molecules. The ion pair amphiphiles are characterized by 1 H-nuclear magnetic resonance, Fourier transform infrared spectroscopy, and X-ray diffraction. Self-assembly properties of amantadine-based ion pair amphiphiles are studied by surface tension determination, transmission electron microscopy, zeta potential, and dynamic light scattering. The aggregation behavior studies indicate that the as-prepared ion pair amphiphiles can self-assemble into vesicles with the size of 200–300 nm in aqueous solution. The drug release results show that the amantadine release rate could be well controlled by incorporating the amantadine-based ion pair vesicles in poly (lactic-co-glycolic acid)-poly (ethylene glycol)-poly (lactic-co-glycolic acid) (PLGA–PEG–PLGA) copolymer hydrogel. The drug release from the AT–OA vesicle-loaded PLGA–PEG–PLGA hydrogel is significantly inhibited in comparison with the AT-loaded PLGA–PEG–PLGA hydrogel. The present work thus demonstrates that the vesicle-loaded hydrogel is a good candidate for the drug delivery system with long-term controlled drug release behavior

Recovery and redispersion of gold nanoparticles using the self-assembly of a pH sensitive zwitterionic amphiphile.

Science.gov (United States)

Morita-Imura, Clara; Imura, Yoshiro; Kawai, Takeshi; Shindo, Hitoshi

2014-11-04

The pH-responsive self-assembly of zwitterionic amphiphile C16CA was expanded to the recovery of gold (Au) nanoparticles for environmentally friendly chemistry applications. Multilayered lamellae at pH ∼ 4 were successfully incorporated into nanoparticles by dispersion. Redispersion of nanoparticles was achieved under basic conditions by the transition of self-assembly.

Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules.

Science.gov (United States)

Higashi, Taishi; Iohara, Daisuke; Motoyama, Keiichi; Arima, Hidetoshi

2018-01-01

Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

Preparation and Characterization of Amphiphilic Triblock Terpolymer-Based Nanofibers as Antifouling Biomaterials

KAUST Repository

Cho, Youngjin

2012-05-14

Antifouling surfaces are critical for the good performance of functional materials in various applications including water filtration, medical implants, and biosensors. In this study, we synthesized amphiphilic triblock terpolymers (tri-BCPs, coded as KB) and fabricated amphiphilic nanofibers by electrospinning of solutions prepared by mixing the KB with poly(lactic acid) (PLA) polymer. The resulting fibers with amphiphilic polymer groups exhibited superior antifouling performance to the fibers without such groups. The adsorption of bovine serum albumin (BSA) on the amphiphilic fibers was about 10-fold less than that on the control surfaces from PLA and PET fibers. With the increase of the KB content in the amphiphilic fibers, the resistance to adsorption of BSA was increased. BSA was released more easily from the surface of the amphiphilic fibers than from the surface of hydrophobic PLA or PET fibers. We have also investigated the structural conformation of KB in fibers before and after annealing by contact angle measurements, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and coarse-grained molecular dynamics (CGMD) simulation to probe the effect of amphiphilic chain conformation on antifouling. The results reveal that the amphiphilic KB was evenly distributed within as-spun hybrid fibers, while migrated toward the core from the fiber surface during thermal treatment, leading to the reduction in antifouling. This suggests that the antifouling effect of the amphiphilic fibers is greatly influenced by the arrangement of amphiphilic groups in the fibers. © 2012 American Chemical Society.

Multivalency in supramolecular chemistry and nanofabrication

NARCIS (Netherlands)

Mulder, A.; Huskens, Jurriaan; Reinhoudt, David

2004-01-01

Multivalency is a powerful and versatile self-assembly pathway that confers unique thermodynamic and kinetic behavior onto supramolecular complexes. The diversity of the examples of supramolecular multivalent systems discussed in this perspective shows that the concept of multivalency is a general

Supramolecular architectures in layer-by-layer films of single-walled carbon nanotubes, chitosan and cobalt (II) phthalocyanine

Energy Technology Data Exchange (ETDEWEB)

Sousa Luz, Roberto A. de; Martins, Marccus Victor A.; Magalhaes, Janildo L. [Departamento de Quimica, Centro de Ciencias da Natureza, Universidade Federal do Piaui, Teresina - PI, CEP 64049-550 (Brazil); Siqueira, Jose R. [Instituto de Ciencias Exatas, Naturais e Educacao, Universidade Federal do Triangulo Mineiro, Uberaba - MG, CEP 38025-180, Brazil (Brazil); Zucolotto, Valtencir; Oliveira, Osvaldo N. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Sao Carlos - SP, CEP 13560-970 (Brazil); Crespilho, Frank N. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Santo Andre - SP, CEP 09210-170 (Brazil); Cantanhede da Silva, Welter, E-mail: welter@ufpi.edu.br [Departamento de Quimica, Centro de Ciencias da Natureza, Universidade Federal do Piaui, Teresina - PI, CEP 64049-550 (Brazil)

2011-11-01

Highlights: {yields} Platforms were assembled from cobalt phthalocyanine, chitosan and carbon nanotubes. {yields} Supramolecular organization of multilayer films was investigated. {yields} Increase of the supramolecular charge transfer after carbon nanotube incorporation. {yields} Functional modulation based on constitutional dynamic chemistry was achieved. - Abstract: The building of supramolecular structures in nanostructured films has been exploited for a number of applications, with the film properties being controlled at the molecular level. In this study, we report on the layer-by-layer (LbL) films combining cobalt (II) tetrasulfonated phthalocyanine (CoTsPc), chitosan (Chit) and single-walled carbon nanotubes (SWCNTs) in two architectures, {l_brace}Chit/CoTsPc{r_brace}{sub n} and {l_brace}Chit-SWCNTs/CoTsPc{r_brace}{sub n} (n = 1-10). The physicochemical properties of the films were evaluated and the multilayer formation was monitored with microgravimetry measurements using a quartz microbalance crystal and an electrochemical technique. According to atomic force microscopy (AFM) results, the incorporation of SWCNTs caused the films to be thicker, with a thickness ca. 3 fold that of a 2-bilayer LbL film with no SWCNTs. Cyclic voltammetry revealed a quasi-reversible, one electron process with E{sub 1/2} at -0.65 V (vs SCE) and an irreversible oxidation process at 0.80 V in a physiological medium for both systems, which can be attributed to [CoTsPc(I)]{sup 5-}/[CoTsPc(II)]{sup 4-} and CoTsPc(II) to CoTsPc(III), respectively. The {l_brace}Chit-SWCNTs/CoTsPc{r_brace}{sub 5} multilayer film exhibited an increased faradaic current, probably associated with the supramolecular charge transfer interaction between cobalt phthalocyanine and SWCNTs. The results demonstrate that an intimate contact at the supramolecular level between functional SWCNTs immobilized into biocompatible chitosan polymer and CoTsPc improves the electron flow from CoTsPc redox sites to the

Hydrogen bonded supramolecular materials

CERN Document Server

Li, Zhan-Ting

2015-01-01

This book is an up-to-date text covering topics in utilizing hydrogen bonding for constructing functional architectures and supramolecular materials. The first chapter addresses the control of photo-induced electron and energy transfer. The second chapter summarizes the formation of nano-porous materials. The following two chapters introduce self-assembled gels, many of which exhibit unique functions. Other chapters cover the advances in supramolecular liquid crystals and the versatility of hydrogen bonding in tuning/improving the properties and performance of materials. This book is designed

Yolk–shell Fe3O4@SiO2@PMO: amphiphilic magnetic nanocomposites as an adsorbent and a catalyst with high efficiency and recyclability

KAUST Repository

Dai, Jinyu; Zou, Houbing; Wang, Runwei; Wang, Yu; Shi, Zhiqiang; Qiu, Shilun

2017-01-01

This study describes the preparation of a multifunctional adsorptive catalyst by the incorporation of ligand groups within the channels of magnetic amphiphilic nanocomposites and attached with Pd nanoparticles. It was clearly demonstrated that Pd2

Lipase polystyrene giant amphiphiles.

Science.gov (United States)

Velonia, Kelly; Rowan, Alan E; Nolte, Roeland J M

2002-04-24

A new type of giant amphiphilic molecule has been synthesized by covalently connecting a lipase enzyme headgroup to a maleimide-functionalized polystyrene tail (40 repeat units). The resulting biohybrid forms catalytic micellar rods in water.

Multilayers of Fluorinated Amphiphilic Polyions for Marine Fouling Prevention

NARCIS (Netherlands)

Zhu, X.; Guo, S.; Janczewski, D.; Parra-Velandia, F.J.; Teo, S.L-M.; Vancso, Gyula J.

2014-01-01

Sequential layer-by-layer (LbL) deposition of polyelectrolytes followed by chemical cross-linking was investigated as a method to fabricate functional amphiphilic surfaces for marine biofouling prevention applications. A novel polyanion, grafted with amphiphilic perfluoroalkyl polyethylene glycol

An Experimental and Molecular Dynamics Investigation into the Amphiphilic Nature of Sulforhodamine B

OpenAIRE

Polat, Baris E.; Lin, Shangchao; Mendenhall, Jonathan D.; VanVeller, Brett; Langer, Robert; Blankschtein, Daniel

2011-01-01

Sulforhodamine B (SRB), a common fluorescent dye, is often considered to be a purely hydrophilic molecule, having no impact on bulk or interfacial properties of aqueous solutions. This assumption is due to the high water solubility of SRB relative to most fluorescent probes. However, in the present study, we demonstrate that SRB is in fact an amphiphile, with the ability to adsorb at an air/water interface and to incorporate into sodium dodecyl sulfate (SDS) micelles. In fact, SRB reduces the...

Recombinant Amphiphilic Protein Micelles for Drug Delivery

OpenAIRE

Kim, Wookhyun; Xiao, Jiantao; Chaikof, Elliot L.

2011-01-01

Amphiphilic block polypeptides can self-assemble into a range of nanostructures in solution, including micelles and vesicles. Our group has recently described the capacity of recombinant amphiphilic diblock copolypeptides to form highly stable micelles. In this report, we demonstrate the utility of protein nanoparticles to serve as a vehicle for controlled drug delivery. Drug-loaded micelles were produced by encapsulating dipyridamole as a model hydrophobic drug with anti-inflammatory activit...

Glucose-neopentyl glycol (GNG) amphiphiles for membrane protein study

DEFF Research Database (Denmark)

Chae, Pil Seok; Rana, Rohini R; Gotfryd, Kamil

2013-01-01

The development of a new class of surfactants for membrane protein manipulation, "GNG amphiphiles", is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo ...

Magnetism: a supramolecular function

International Nuclear Information System (INIS)

Decurtins, S.; Pellaux, R.; Schmalle, H.W.

1996-01-01

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 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

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.

Self-Healing Natural Rubber with Tailorable Mechanical Properties Based on Ionic Supramolecular Hybrid Network.

Science.gov (United States)

Xu, Chuanhui; Cao, Liming; Huang, Xunhui; Chen, Yukun; Lin, Baofeng; Fu, Lihua

2017-08-30

In most cases, the strength of self-healing supramolecular rubber based on noncovalent bonds is in the order of KPa, which is a challenge for their further applications. Incorporation of conventional fillers can effectively enhance the strength of rubbers, but usually accompanied by a sacrifice of self-healing capability due to that the filler system is independent of the reversible supramolecular network. In the present work, in situ reaction of methacrylic acid (MAA) and excess zinc oxide (ZnO) was realized in natural rubber (NR). Ionic cross-links in NR matrix were obtained by limiting the covalent cross-linking of NR molecules and allowing the in situ polymerization of MAA/ZnO. Because of the natural affinity between Zn 2+ ion-rich domains and ZnO, the residual nano ZnO participated in formation of a reversible ionic supramolecular hybrid network, thus having little obstructions on the reconstruction of ionic cross-links. Meanwhile, the well dispersed residual ZnO could tailor the mechanical properties of NR by changing the MAA/ZnO molar ratios. The present study thus provides a simple method to fabricate a new self-healing NR with tailorable mechanical properties that may have more potential applications.

Amphiphilic chitosan derivatives as carrier agents for rotenone

Science.gov (United States)

Kamari, Azlan; Aljafree, Nurul Farhana Ahmad

2017-08-01

In the present study, the feasibility of amphiphilic chitosan derivatives, namely oleoyl carboxymethyl chitosan (OCMCs), N,N-dimethylhexadecyl carboxymethyl chitosan (DCMCs) and deoxycholic acid carboxymethyl chitosan (DACMCs) as carrier agents for rotenone in water-insoluble pesticide formulations was investigated. Fourier Transform Infrared (FTIR) Spectrometer, CHN-O Elemental Analyser (CHN-O) and Transmission Electron Microscope (TEM) were used to characterise amphiphilic chitosan derivatives. The critical micelle concentration (CMC) of amphiphilic chitosan derivatives was determined using a Fluorescence Spectrometer. A High Performance Liquid Chromatography (HPLC) was used to determine the ability of OCMCs, DCMCs and DACMCs to load and release rotenone in an in vitro system. Based on TEM analysis, results have shown that amphiphilic chitosan derivatives formed self-assembly and exhibited spherical shape. The CMC values determined for OCMCs, DCMCs and DACMCs were 0.093, 0.098 and 0.468 mg/mL, respectively. The encapsulation efficiency (EE) values for the materials were more than 97.0%, meanwhile the loading capacity (LC) values were greater than 0.90%. OCMCs, DCMCs and DACMCs micelles exhibited an excellent ability to control the release of rotenone, of which 90.0% of rotenone was released within 40 to 52 h. In conclusion, OCMCs, DCMCs and DACMCs possess several key features to act as effective carrier agents for rotenone. Overall, amphiphilic chitosan derivatives produced in this study were successfully increased the solubility of rotenone by 49.0 times higher than free rotenone.

Supramolecular materials based on hydrogen-bonded polymers

NARCIS (Netherlands)

ten Brinke, Gerrit; Ruokolainen, Janne; Ikkala, Olli; Binder, W

2007-01-01

Combining supramolecular principles with block copolymer self-assembly offers unique possibilities to create materials with responsive and/or tunable properties. The present chapter focuses on supramolecular materials based on hydrogen bonding and (block co-) polymers. Several cases will be

Design of Molecular Materials: Supramolecular Engineering

Science.gov (United States)

Simon, Jacques; Bassoul, Pierre

2001-02-01

This timely and fascinating book is destined to be recognised as THE book on supramolecular engineering protocols. It covers this sometimes difficult subject in an approachable form, gathering together information from many sources. Supramolecular chemistry, which links organic chemistry to materials science, is one of the fastest growth areas of chemistry research. This book creates a correlation between the structure of single molecules and the physical and chemical properties of the resulting materials. By making systematic changes to the component molecules, the resulting solid can be engineered for optimum performance. There is a clearly written development from synthesis of designer molecules to properties of solids and further on to devices and complex materials systems, providing guidelines for mastering the organisation of these systems. Topics covered include: Systemic chemistry Molecular assemblies Notions of symmetry Supramolecular engineering Principe de Curie Organisation in molecular media Molecular semiconductors Industrial applications of molecular materials This superb book will be invaluable to researchers in the field of supramolecular materials and also to students and teachers of the subject.

Dissolving Microneedle Arrays for Transdermal Delivery of Amphiphilic Vaccines.

Science.gov (United States)

An, Myunggi; Liu, Haipeng

2017-07-01

Amphiphilic vaccine based on lipid-polymer conjugates is a new type of vaccine capable of self-delivering to the immune system. When injected subcutaneously, amphiphilic vaccines efficiently target antigen presenting cells in the lymph nodes (LNs) via a unique albumin-mediated transport and uptake mechanism and induce potent humoral and cellular immune responses. However, whether this new type of vaccine can be administrated via a safe, convenient microneedle-based transdermal approach remains unstudied. For such skin barrier-disruption systems, a simple application of microneedle arrays (MNs) is desired to disrupt the stratum corneum, and for rapid and pain-free self-administration of vaccines into the skin, the anatomic place permeates with an intricate mesh of lymphatic vessels draining to LNs. Here the microneedle transdermal approach is combined with amphiphilic vaccines to create a simple delivery approach which efficiently traffic molecular vaccines into lymphatics and draining LNs. The rapid release of amphiphilic vaccines into epidermis upon application of dissolving MNs to the skin of mice generates potent cellular and humoral responses, comparable or superior to those elicited by traditional needle-based immunizations. The results suggest that the amphiphilic vaccines delivered by dissolving MNs can provide a simple and safer vaccination method with enhanced vaccine efficacy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dynamic reciprocity in bio-inspired supramolecular materials

NARCIS (Netherlands)

Bastings, M.M.C.

2012-01-01

Dynamic reciprocity, the spatio-temporal bidirectional process between evolving partners in a functional system is not only found in nature, but also applies to supramolecularly assembling architectures. In this thesis, the focus was on the understanding of nature-inspired supramolecular

Glucose-neopentyl glycol (GNG) amphiphiles for membrane protein study.

Science.gov (United States)

Chae, Pil Seok; Rana, Rohini R; Gotfryd, Kamil; Rasmussen, Søren G F; Kruse, Andrew C; Cho, Kyung Ho; Capaldi, Stefano; Carlsson, Emil; Kobilka, Brian; Loland, Claus J; Gether, Ulrik; Banerjee, Surajit; Byrne, Bernadette; Lee, John K; Gellman, Samuel H

2013-03-21

The development of a new class of surfactants for membrane protein manipulation, "GNG amphiphiles", is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo et al. (Science, 2012, 337, 473).

Competitive Binding of Natural Amphiphiles with Graphene Derivatives

Science.gov (United States)

Radic, Slaven; Geitner, Nicholas K.; Podila, Ramakrishna; Käkinen, Aleksandr; Chen, Pengyu; Ke, Pu Chun; Ding, Feng

2013-01-01

Understanding the transformation of graphene derivatives by natural amphiphiles is essential for elucidating the biological and environmental implications of this emerging class of engineered nanomaterials. Using rapid discrete-molecular-dynamics simulations, we examined the binding of graphene and graphene oxide with peptides, fatty acids, and cellulose, and complemented our simulations by experimental studies of Raman spectroscopy, FTIR, and UV-Vis spectrophotometry. Specifically, we established a connection between the differential binding and the conformational flexibility, molecular geometry, and hydrocarbon content of the amphiphiles. Importantly, our dynamics simulations revealed a Vroman-like competitive binding of the amphiphiles for the graphene oxide substrate. This study provides a mechanistic basis for addressing the transformation, evolution, transport, biocompatibility, and toxicity of graphene derivatives in living systems and the natural environment. PMID:23881402

Enhanced intermolecular forces in supramolecular polymer nanocomposites

Directory of Open Access Journals (Sweden)

F. Lin

2017-09-01

Full Text Available Ureido-pyrimidone (Upy can dimerize in a self-complementary array of quadruple hydrogen bonds. In this paper, supramolecular polymer composites were prepared by blending Upy functionalized nanosilica with Upy end-capped polycarbonatediol. Surface characteristics of Upy functionalized nanosilica and influences of supramolecular forces on interfacial binding were researched. Fourier transform infrared spectroscopy (FTIR, Nuclear magnetic resonance (NMR and Gel permeation chromatography (GPC were used to characterize the synthesized molecules. Grafting ratio of Upy segments on the surface of nanosilica was analysed by Thermogravimetic analysis (TGA. Hydrophobicity and morphology of Upy modified nanosilica were analysed by Contact angle tester and Scanning electron microscope (SEM. Furthermore, dynamic thermo mechanical properties, mechanical properties and distribution of nanosilica in supramolecular polymer composites were also researched. Compared with the matrix resin, tensile stress and young's modulus of supramolecular polymer composites containing 5 wt% modified nanosilica were increased by 292 and 198% respectively.

Progress Toward the Clinical Translation of Bioinspired Peptide and Protein Assemblies.

Science.gov (United States)

Hainline, Kelly M; Fries, Chelsea N; Collier, Joel H

2018-03-01

Supramolecular materials composed of proteins and peptides have been receiving considerable attention toward a range of diseases and conditions from vaccines to drug delivery. Owing to the relative newness of this class of materials, the bulk of work to date has been preclinical. However, examples of approved treatments particularly in vaccines, dentistry, and hemostasis demonstrate the translational potential of supramolecular polypeptides. Critical milestones in the clinical development of this class of materials and currently approved supramolecular polypeptide therapies are described in this study. Additional examples of not-yet-approved materials that are steadily advancing toward clinical use are also featured. Spherical assemblies such as virus-like particles, designed protein nanoparticles, and spherical peptide amphiphiles are highlighted, followed by fiber-forming systems such as fibrillizing peptides, fiber-forming peptide-amphiphiles, and filamentous bacteriophages. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Ni, Lubin [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Zhang, Wang [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 151-742 (Korea, Republic of); Wu, Zhen; Sun, Chunyu; Cai, Yin; Yang, Guang; Chen, Ming [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China); Piao, Yuanzhe, E-mail: parkat9@snu.ac.kr [Graduate School of Convergence Science and Technology, Seoul National University, Seoul, 151-742 (Korea, Republic of); Diao, Guowang, E-mail: gwdiao@yzu.edu.cn [College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, Jiangsu (China)

2017-02-28

Graphical abstract: Supramolecular assembled three-dimensdional graphene-based architectures were built by host-guest interactions of β-cyclodextrin polymers(β-CDPs) with adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD), exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. - Highlights: • Supramolecular assembled three-Dimensional (3D) graphene was first fabricated by host-guest interactions of β-CDPs with PEG-AD linkers. • The incorporation of PEG-AD linker into rGO sheets can provide efficient 3D electron transfer pathways and ion diffusion channels. • The 3D self-assembled graphene exhibits high specific capacitance, remarkable rate capability, and excellent cycling stability. • This study shed new lights to design 3D self-assembled graphene materials and their urgent applications in energy storage. - Abstract: Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms

Supramolecular assembled three-dimensional graphene hybrids: Synthesis and applications in supercapacitors

International Nuclear Information System (INIS)

Ni, Lubin; Zhang, Wang; Wu, Zhen; Sun, Chunyu; Cai, Yin; Yang, Guang; Chen, Ming; Piao, Yuanzhe; Diao, Guowang

2017-01-01

Graphical abstract: Supramolecular assembled three-dimensdional graphene-based architectures were built by host-guest interactions of β-cyclodextrin polymers(β-CDPs) with adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD), exhibit significantly improved electrochemical performances of supercapacitor in terms of high specific capacitance, remarkable rate capability, and excellent cycling stability compared to pristine reduced graphene oxide. - Highlights: • Supramolecular assembled three-Dimensional (3D) graphene was first fabricated by host-guest interactions of β-CDPs with PEG-AD linkers. • The incorporation of PEG-AD linker into rGO sheets can provide efficient 3D electron transfer pathways and ion diffusion channels. • The 3D self-assembled graphene exhibits high specific capacitance, remarkable rate capability, and excellent cycling stability. • This study shed new lights to design 3D self-assembled graphene materials and their urgent applications in energy storage. - Abstract: Graphene-based materials have received worldwide attention in the focus of forefront energy storage investigations. Currently, the design of novel three-dimensional (3D) graphene structures with high energy capability, superior electron and ion conductivity, and robust mechanical flexibility is still a great challenge. Herein, we have successfully demonstrated a novel approach to fabricate 3D assembled graphene through the supramolecular interactions of β-cyclodextrin polymers (β-CDP) with an adamantine end-capped poly(ethylene oxide) polymer linker (PEG-AD). The incorporation of PEG-AD linker into rGO sheets increased the interlayer spacing of rGO sheets to form 3D graphene materials, which can provide efficient 3D electron transfer pathways and ion diffusion channels, and facilitate the infiltration of gel electrolyte. The as-prepared 3D self-assembled graphene materials exhibit significantly improved electrochemical performances of supercapacitor in terms

Micellar Surfactant Association in the Presence of a Glucoside-based Amphiphile Detected via High-Throughput Small Angle X-ray Scattering

Energy Technology Data Exchange (ETDEWEB)

Stanic, Vesna [Brazilian Synchrotron Light Source, Campinas (Brazil); Broadbent, Charlotte [Columbia Univ., New York, NY (United States). Engineering Dept.; DiMasi, Elaine [Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Division; Galleguillos, Ramiro [Lubrizol Advanced Materials, Cleveland, OH (United States); Woodward, Valerie [Lubrizol Advanced Materials, Cleveland, OH (United States)

2016-11-14

The interactions of mixtures of anionic and amphoteric surfactants with sugar amphiphiles were studied via high throughput small angle x-ray scattering (SAXS). The sugar amphiphile was composed of Caprate, Caprylate, and Oleate mixed ester of methyl glucoside, MeGCCO. Optimal surfactant interactions are sought which have desirable physical properties, which must be identified in a cost effective manner that can access the large phase space of possible molecular combinations. X-ray scattering patterns obtained via high throughput SAXS can probe a combinatorial sample space and reveal the incorporation of MeGCCO into the micelles and the molecular associations between surfactant molecules. Such data make it possible to efficiently assess the effects of the new amphiphiles in the formulation. A specific finding of this study is that formulations containing comparatively monodisperse and homogeneous surfactant mixtures can be reliably tuned by addition of NaCl, which swells the surfactant micelles with a monotonic dependence on salt concentration. In contrast, the presence of multiple different surfactants destroys clear correlations with NaCl concentration, even in otherwise similar series of formulations.

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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Solvent induced supramolecular anisotropy in molecular gels

Energy Technology Data Exchange (ETDEWEB)

Rogers, Michael A., E-mail: mroger09@uoguelph.ca [Department of Food Science, University of Guelph, Guelph, Ontario, N3C3X9 (Canada); Corradini, Maria G. [Department of Food Science, University of Massachusetts Amherst, Amherst, MA, 01003 (United States); Emge, Thomas [Department of Chemistry and Biochemistry, Rutgers University, New Brunswick, NJ, 08901 (United States)

2017-06-15

Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

Solvent induced supramolecular anisotropy in molecular gels

International Nuclear Information System (INIS)

Rogers, Michael A.; Corradini, Maria G.; Emge, Thomas

2017-01-01

Herein is the first report of solvent induced anisotropy in 12-hydroxystearic acid self-assembled fibrillar networks. Increasing the chain length of polar solvent, such as nitriles and ketones, tailored the anisotropy of the fibrillar aggregates. 12HSA molecular gels, comprised of alkanes, exhibited an isotropic fibrillar network irrespective of the alkane chain length. In polar solvents, anisotropy, observed using 2D powder x-ray diffraction profiles, is correlated to a fibrillar supramolecular morphologies in long chain nitriles and ketones while sphereulitic crystals are correlated to x-ray diffraction patterns with an isotropic scatter intensity in short chain ketones and nitriles. These changes directly modify the final physical properties of the gels. - Highlights: • 12-HSA self-assembles into crystalline supramolecular morphologies depending on the solvent. • Alkanes, short chain nitriles and ketones led to 12-HSA displaying supramolecular isotropy. • In long chain nitriles and ketones, 12-HSA displays supramolecular anisotropy.

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.

Gelation induced supramolecular chirality: chirality transfer, amplification and application.

Science.gov (United States)

Duan, Pengfei; Cao, Hai; Zhang, Li; Liu, Minghua

2014-08-14

Supramolecular chirality defines chirality at the supramolecular level, and is generated from the spatial arrangement of component molecules assembling through non-covalent interactions such as hydrogen bonding, van der Waals interactions, π-π stacking, hydrophobic interactions and so on. During the formation of low molecular weight gels (LMWGs), one kind of fascinating soft material, one frequently encounters the phenomenon of chirality as well as chiral nanostructures, either from chiral gelators or even achiral gelators. A view of gelation-induced supramolecular chirality will be very helpful to understand the self-assembly process of the gelator molecules as well as the chiral structures, the regulation of the chirality in the gels and the development of the "smart" chiral materials such as chiroptical devices, catalysts and chiral sensors. It necessitates fundamental understanding of chirality transfer and amplification in these supramolecular systems. In this review, recent progress in gelation-induced supramolecular chirality is discussed.

Construction of diverse supramolecular assemblies of dimetal ...

Indian Academy of Sciences (India)

presence or absence of the lattice water molecules are the keys to forming the diverse supramolecular assem- blies. In 1 and 3, ... Supramolecular; hydrogen bonding; flexible ligand; dicarboxylates. 1. ... The reaction mixture was stirred for another 3 to 4 hours at room ..... Funding for this work was provided by IISER, Mohali.

Lyotropic liquid crystalline phase behaviour in amphiphile-protic ionic liquid systems.

Science.gov (United States)

Chen, Zhengfei; Greaves, Tamar L; Fong, Celesta; Caruso, Rachel A; Drummond, Calum J

2012-03-21

Approximate partial phase diagrams for nine amphiphile-protic ionic liquid (PIL) systems have been determined by synchrotron source small angle X-ray scattering, differential scanning calorimetry and cross polarised optical microscopy. The binary phase diagrams of some common cationic (hexadecyltrimethyl ammonium chloride, CTAC, and hexadecylpyridinium bromide, HDPB) and nonionic (polyoxyethylene (10) oleyl ether, Brij 97, and Pluronic block copolymer, P123) amphiphiles with the PILs, ethylammonium nitrate (EAN), ethanolammonium nitrate (EOAN) and diethanolammonium formate (DEOAF), have been studied. The phase diagrams were constructed for concentrations from 10 wt% to 80 wt% amphiphile, in the temperature range 25 °C to >100 °C. Lyotropic liquid crystalline phases (hexagonal, cubic and lamellar) were formed at high surfactant concentrations (typically >50 wt%), whereas at thermal stability of the phases formed by these surfactants persisted to temperatures above 100 °C. The phase behaviour of amphiphile-PIL systems was interpreted by considering the PIL cohesive energy, liquid nanoscale order, polarity and ionicity. For comparison the phase behaviour of the four amphiphiles was also studied in water.

Supramolecular oligothiophene microfibers spontaneously assembled on surfaces or coassembled with proteins inside live cells.

Science.gov (United States)

Barbarella, Giovanna; Di Maria, Francesca

2015-08-18

During the last few decades, multifunctional nano- and microfibers made of semiconducting π-conjugated oligomers and polymers have generated much interest because of a broad range of applications extending from sensing to bioelectronic devices and (opto)electronics. The simplest technique for the fabrication of these anisotropic supramolecular structures is to let the molecules do the work by spontaneous organization driven by the information encoded in their molecular structure. Oligothiophenes-semiconducting and fluorescent compounds that have been extensively investigated for applications in thin-film field-effect transistors and solar cells and to a lesser extent as dyes for fluorescent labeling of proteins, DNA, and live cells-are particularly suited as building blocks for supramolecular architectures because of the peculiar properties of the thiophene ring. Because of the great polarizability of sulfur outer-shell electrons and the consequent facile geometric deformability and adaptability of the ring to the environment, thiophene can generate multiple nonbonding interactions to promote non-covalent connections between blocks. Furthermore, sulfur can be hypervalent, i.e., it can accommodate more than the eight electrons normally associated with s and p shells. Hypervalent oligothiophene-S,S-dioxides whose oxygen atoms can be involved in hydrogen bonding have been synthesized. These compounds are amphiphilic, and some of them are able to spontaneously cross the membrane of live cells. Hypervalent nonbonding interactions of divalent sulfur, defined as weak coordination to a proximate nitrogen or oxygen, have also been invoked in the solid-state packing of many organic molecules and in the architecture of proteins. In this Account, we describe two different types of thiophene-based building blocks that can induce the spontaneous formation of nanostructured microfibers in very different environments. The first, based on the synthesis of "sulfur

Supramolecular polymeric materials via cyclodextrin-guest interactions.

Science.gov (United States)

Harada, Akira; Takashima, Yoshinori; Nakahata, Masaki

2014-07-15

CONSPECTUS: Cyclodextrins (CDs) have many attractive functions, including molecular recognition, hydrolysis, catalysis, and polymerization. One of the most important uses of CDs is for the molecular recognition of hydrophobic organic guest molecules in aqueous solutions. CDs are desirable host molecules because they are environmentally benign and offer diverse functions. This Account demonstrates some of the great advances in the development of supramolecular materials through host-guest interactions within the last 10 years. In 1990, we developed topological supramolecular complexes with CDs, polyrotaxane, and CD tubes, and these preparation methods take advantage of self-organization between the CDs and the polymers. The combination of polyrotaxane with αCD forms a hydrogel through the interaction of αCDs with the OH groups on poly(ethylene glycol). We categorized these polyrotaxane chemistries within main chain type complexes. At the same time, we studied the interactions of side chain type supramolecular complexes with CDs. In these systems the guest molecules modified the polymers and selectively formed inclusion complexes with CDs. The systems that used low molecular weight compounds did not show such selectivity with CDs. The multivalency available within the complex cooperatively enhances the selective binding of CD with guest molecules via the polymer side chains, a phenomenon that is analogous to binding patterns observed in antigen-antibody complexes. To incorporate the molecular recognition properties of CDs within the polymer side chains, we first prepared stimuli-responsive sol-gel switching materials through host-guest interactions. We chose azobenzene derivatives for their response to light and ferrocene derivatives for their response to redox conditions. The supramolecular materials were both redox-responsive and self-healing, and these properties resulted from host-guest interactions. These sol-gels with built in switches gave us insight for

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. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yolk–shell Fe3O4@SiO2@PMO: amphiphilic magnetic nanocomposites as an adsorbent and a catalyst with high efficiency and recyclability

KAUST Repository

Dai, Jinyu

2017-01-20

This study describes the preparation of a multifunctional adsorptive catalyst by the incorporation of ligand groups within the channels of magnetic amphiphilic nanocomposites and attached with Pd nanoparticles. It was clearly demonstrated that Pd2+ was adsorbed by ligand-functionalized materials in water, and then Pd2+ was coordinated with ligand groups. Finally, the Pd nanoparticles were produced via an in situ reduction of Pd2+ by ligand groups through a simple hydrothermal process. Moreover, amphiphilic nanomaterials are viewed as excellent collectors of hydrophobic contaminants in water. The immobilized catalytic active sites with ligand-functionalized nanocomposites were allowed for maximal exposure to the reactants with minimal leaching of the Pd nanoparticles. The unique amphiphilic nanocomposites enabled selective oxidation of alcohols to proceed efficiently in water under aerobic conditions. Moreover, this nanocomposite catalyst could be completely recovered using an external magnet due to the superparamagnetic behavior of Fe3O4 and can be recycled with sustained selectivity and activity.

Supramolecular systems chemistry

NARCIS (Netherlands)

Mattia, Elio; Otto, Sijbren

The field of supramolecular chemistry focuses on the non-covalent interactions between molecules that give rise to molecular recognition and self-assembly processes. Since most non-covalent interactions are relatively weak and form and break without significant activation barriers, many

Exploring single chain amphiphile self-assembly and their possible roles in light transduction

DEFF Research Database (Denmark)

Monnard, Pierre-Alain

2011-01-01

Self-assembled structures of single-chain amphiphiles have been used as hosts for biochemical, and chemical reactions. Their use as models for protocells (i.e., precursors to the first biological cells) has been extensively researched by various groups because the availability of single chain......: the medium composition in terms of ionic strengths and the medium physical parameters, such as temperature, significantly influence the formation of structures, as well as their subsequent stability. In addition, membranes composed of a single amphiphile type seem to be implausible as no potential amphiphile...... source studied to date can supply one single type of amphiphile at concentrations conducive to self-assembly. Mixtures of single-chain amphiphiles were therefore proposed to better model primitive membranes and potentially enhance their structural integrity1-3. Recently, we have established that complex...

Non-equilibrium supramolecular polymerization.

Science.gov (United States)

Sorrenti, Alessandro; Leira-Iglesias, Jorge; Markvoort, Albert J; de Greef, Tom F A; Hermans, Thomas M

2017-09-18

Supramolecular polymerization has been traditionally focused on the thermodynamic equilibrium state, where one-dimensional assemblies reside at the global minimum of the Gibbs free energy. The pathway and rate to reach the equilibrium state are irrelevant, and the resulting assemblies remain unchanged over time. In the past decade, the focus has shifted to kinetically trapped (non-dissipative non-equilibrium) structures that heavily depend on the method of preparation (i.e., pathway complexity), and where the assembly rates are of key importance. Kinetic models have greatly improved our understanding of competing pathways, and shown how to steer supramolecular polymerization in the desired direction (i.e., pathway selection). The most recent innovation in the field relies on energy or mass input that is dissipated to keep the system away from the thermodynamic equilibrium (or from other non-dissipative states). This tutorial review aims to provide the reader with a set of tools to identify different types of self-assembled states that have been explored so far. In particular, we aim to clarify the often unclear use of the term "non-equilibrium self-assembly" by subdividing systems into dissipative, and non-dissipative non-equilibrium states. Examples are given for each of the states, with a focus on non-dissipative non-equilibrium states found in one-dimensional supramolecular polymerization.

Supramolecular biomaterials : a modular approach towards tissue engineering

NARCIS (Netherlands)

Dankers, P.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

Hydrophobicity and thermodynamic response for aqueous solutions of amphiphiles

Science.gov (United States)

Zemánková, Katerina; Troncoso, Jacobo; Cerdeiriña, Claudio A.; Romaní, Luis; Anisimov, Mikhail A.

2016-06-01

The anomalous behavior of aqueous solutions of amphiphiles in the water-rich region is analyzed via a phenomenological approach that utilizes the isobaric heat capacity Cp as an experimental probe. We report extensive data for solutions of 14 amphiphiles as a function of temperature at atmospheric pressure. Beyond that, Cp data but also isobaric thermal expansivities and isothermal compressibilities for three solutions of tert-butanol as a function of both temperature and pressure are presented. Results rule out the possibility that the observed phenomenology is associated with the anomalous thermodynamics of pure water. Indeed, our Cp data, quantitatively consistent with recent spectroscopic analyses, suggest that water-mediated interactions between the nonpolar parts of amphiphiles are at the origin of anomalies, with the effects of such "hydrophobic aggregation" being observed at mole fractions as small as 0.01. Physicochemical details like the size, the electronic charge distribution and the geometry of amphiphile molecules as well as third-order derivatives of the Gibbs energy and the associated Koga lines support the above claims while they further contribute to characterizing the role of hydrophobicity in these phenomena. Progress with a view to gain a deeper, more concrete understanding remains.

Biocompatible Amphiphilic Hydrogel-Solid Dimer Particles as Colloidal Surfactants.

Science.gov (United States)

Chen, Dong; Amstad, Esther; Zhao, Chun-Xia; Cai, Liheng; Fan, Jing; Chen, Qiushui; Hai, Mingtan; Koehler, Stephan; Zhang, Huidan; Liang, Fuxin; Yang, Zhenzhong; Weitz, David A

2017-12-26

Emulsions of two immiscible liquids can slowly coalesce over time when stabilized by surfactant molecules. Pickering emulsions stabilized by colloidal particles can be much more stable. Here, we fabricate biocompatible amphiphilic dimer particles using a hydrogel, a strongly hydrophilic material, and achieve large contrast in the wetting properties of the two bulbs, resulting in enhanced stabilization of emulsions. We generate monodisperse single emulsions of alginate and shellac solution in oil using a flow-focusing microfluidics device. Shellac precipitates from water and forms a solid bulb at the periphery of the droplet when the emulsion is exposed to acid. Molecular interactions result in amphiphilic dimer particles that consist of two joined bulbs: one hydrogel bulb of alginate in water and the other hydrophobic bulb of shellac. Alginate in the hydrogel compartment can be cross-linked using calcium cations to obtain stable particles. Analogous to surfactant molecules at the interface, the resultant amphiphilic particles stand at the water/oil interface with the hydrogel bulb submerged in water and the hydrophobic bulb in oil and are thus able to stabilize both water-in-oil and oil-in-water emulsions, making these amphiphilic hydrogel-solid particles ideal colloidal surfactants for various applications.

Detection of an amphiphilic biosample in a paper microchannel based on length.

Science.gov (United States)

Chen, Yu-Tzu; Yang, Jing-Tang

2015-01-01

We developed a simple method to achieve semiquantitative detection of an amphiphilic biosample through measuring the length of flow on a microfluidic analytical device (μPAD) based on paper. When an amphiphilic sample was dripped into a straight microchannel defined with a printed wax barrier (hydrophobic) on filter paper (hydrophilic), the length of flow was affected by the reciprocal effect between the sample, the filter-paper channel and the wax barrier. The flow length decreased with increasing concentration of an amphiphilic sample because of adsorption of the sample on the hydrophobic barrier. Measurement of the flow length enabled a determination of the concentration of the amphiphilic sample. The several tested samples included surfactants (Tween 20 and Triton X-100), oligonucleotides (DNA), bovine serum albumin (BSA), human albumin, nitrite, glucose and low-density lipoprotein (LDL). The results show that the measurement of the flow length determined directly the concentration of an amphiphilic sample, whereas a non-amphiphilic sample was not amenable to this method. The proposed method features the advantages of small cost, simplicity, convenience, directness, rapidity (<5 min) and requirement of only a small volume (5 μL) of sample, with prospective applications in developing areas and sites near patients for testing at a point of care (POCT).

3D Printing Polymers with Supramolecular Functionality for Biological Applications.

Science.gov (United States)

Pekkanen, Allison M; Mondschein, Ryan J; Williams, Christopher B; Long, Timothy E

2017-09-11

Supramolecular chemistry continues to experience widespread growth, as fine-tuned chemical structures lead to well-defined bulk materials. Previous literature described the roles of hydrogen bonding, ionic aggregation, guest/host interactions, and π-π stacking to tune mechanical, viscoelastic, and processing performance. The versatility of reversible interactions enables the more facile manufacturing of molded parts with tailored hierarchical structures such as tissue engineered scaffolds for biological applications. Recently, supramolecular polymers and additive manufacturing processes merged to provide parts with control of the molecular, macromolecular, and feature length scales. Additive manufacturing, or 3D printing, generates customizable constructs desirable for many applications, and the introduction of supramolecular interactions will potentially increase production speed, offer a tunable surface structure for controlling cell/scaffold interactions, and impart desired mechanical properties through reinforcing interlayer adhesion and introducing gradients or self-assembled structures. This review details the synthesis and characterization of supramolecular polymers suitable for additive manufacture and biomedical applications as well as the use of supramolecular polymers in additive manufacturing for drug delivery and complex tissue scaffold formation. The effect of supramolecular assembly and its dynamic behavior offers potential for controlling the anisotropy of the printed objects with exquisite geometrical control. The potential for supramolecular polymers to generate well-defined parts, hierarchical structures, and scaffolds with gradient properties/tuned surfaces provides an avenue for developing next-generation biomedical devices and tissue scaffolds.

Bola-amphiphile self-assembly

DEFF Research Database (Denmark)

Svaneborg, Carsten

2012-01-01

Bola-amphiphiles are rod-like molecules where both ends of the molecule likes contact with water, while the central part of the molecule dislikes contact with water. What do such molecules do when they are dissolved in water? They self-assemble into micelles. This is a Dissipartive particle...... dynamics simulation of this self-assembly behaviour....

Trapping of polycyclic aromatic hydrocarbons by amphiphilic cyclodextrin functionalized polypropylene nonwovens

DEFF Research Database (Denmark)

Lumholdt, Ludmilla; Nielsen, Ronnie Bo Højstrup; Larsen, Kim Lambertsen

of the textile fibers. In this study we present the ability of amphiphilic CD coated polypropylene nonwovens to trap 8 different polycyclic aromatic hydrocarbons/endocrine disruptors from aqueous solutions thus demonstrating the potential of using the amphiphilic cyclodextrins for water purification....

Supramolecular chemistry: from molecular information towards self-organization and complex matter

International Nuclear Information System (INIS)

Lehn, Jean-Marie

2004-01-01

Molecular chemistry has developed a wide range of very powerful procedures for constructing ever more sophisticated molecules from atoms linked by covalent bonds. Beyond molecular chemistry lies supramolecular chemistry, which aims at developing highly complex chemical systems from components interacting via non-covalent intermolecular forces. By the appropriate manipulation of these interactions, supramolecular chemistry became progressively the chemistry of molecular information, involving the storage of information at the molecular level, in the structural features, and its retrieval, transfer, and processing at the supramolecular level, through molecular recognition processes operating via specific interactional algorithms. This has paved the way towards apprehending chemistry also as an information science. Numerous receptors capable of recognizing, i.e. selectively binding, specific substrates have been developed, based on the molecular information stored in the interacting species. Suitably functionalized receptors may perform supramolecular catalysis and selective transport processes. In combination with polymolecular organization, recognition opens ways towards the design of molecular and supramolecular devices based on functional (photoactive, electroactive, ionoactive, etc) components. A step beyond preorganization consists in the design of systems undergoing self-organization, i.e. systems capable of spontaneously generating well-defined supramolecular architectures by self-assembly from their components. Self-organization processes, directed by the molecular information stored in the components and read out at the supramolecular level through specific interactions, represent the operation of programmed chemical systems. They have been implemented for the generation of a variety of discrete functional architectures of either organic or inorganic nature. Self-organization processes also give access to advanced supramolecular materials, such as

Engineering responsive supramolecular biomaterials: Toward smart therapeutics.

Science.gov (United States)

Webber, Matthew J

2016-09-01

Engineering materials using supramolecular principles enables generalizable and modular platforms that have tunable chemical, mechanical, and biological properties. Applying this bottom-up, molecular engineering-based approach to therapeutic design affords unmatched control of emergent properties and functionalities. In preparing responsive materials for biomedical applications, the dynamic character of typical supramolecular interactions facilitates systems that can more rapidly sense and respond to specific stimuli through a fundamental change in material properties or characteristics, as compared to cases where covalent bonds must be overcome. Several supramolecular motifs have been evaluated toward the preparation of "smart" materials capable of sensing and responding to stimuli. Triggers of interest in designing materials for therapeutic use include applied external fields, environmental changes, biological actuators, applied mechanical loading, and modulation of relative binding affinities. In addition, multistimuli-responsive routes can be realized that capture combinations of triggers for increased functionality. In sum, supramolecular engineering offers a highly functional strategy to prepare responsive materials. Future development and refinement of these approaches will improve precision in material formation and responsiveness, seek dynamic reciprocity in interactions with living biological systems, and improve spatiotemporal sensing of disease for better therapeutic deployment.

Amphiphilic star block copolymers as gene carrier Part I: Synthesis via ATRP using calix[4]resorcinarene-based initiators and characterization

Energy Technology Data Exchange (ETDEWEB)

Zheng, Anna; Xue, Yan; Wei, Dafu [Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Guan, Yong, E-mail: yguan@ecust.edu.cn [Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Xiao, Huining [Department of Chemical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3 (Canada)

2013-01-01

In this work, a cationic star polymer [poly(2-dimethylamino)ethyl methacrylate (PDMAEMA)] was prepared via atom transfer radical polymerization (ATRP), using brominated calix[4]resorcinarene as an initiator. Hydrophobic moieties, methyl methacrylate (MMA) and butyl acrylate (BA), were further incorporated via 'one-pot' method. Well-defined eight-armed star block copolymers bearing hydrophilic blocks inside and hydrophobic blocks outside were synthesized. The molecular weight, particle size, electrophoretic mobility and apparent charge density were determined by gel permeation chromatography (GPC), dynamic light scattering (DLS), phase analysis light scattering (PALS) and colloidal titration, respectively. The zeta potentials and apparent charge densities of the products exhibited the characteristics of polyelectrolyte. The incorporation of hydrophobic moieties generated electrostatic screening effect. The as-synthesized amphiphilic star copolymer is promising as a thermo-sensitive gene carrier for gene therapy. Highlights: Black-Right-Pointing-Pointer Amphiphilic cationic star block copolymers with well-controlled structures were prepared via ATRP. Black-Right-Pointing-Pointer The molecular structures and properties of the initiator and copolymers were systematically characterized. Black-Right-Pointing-Pointer The products exhibited the positive charged character, and hydrophobic moieties generated electrostatic screening effect.

Supramolecular tunneling junctions

NARCIS (Netherlands)

Wimbush, K.S.

2012-01-01

In this study a variety of supramolecular tunneling junctions were created. The basis of these junctions was a self-assembled monolayer of heptathioether functionalized ß-cyclodextrin (ßCD) formed on an ultra-flat Au surface, i.e., the bottom electrode. This gave a well-defined hexagonally packed

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.

Preparation and Characterization of Amphiphilic Triblock Terpolymer-Based Nanofibers as Antifouling Biomaterials

KAUST Repository

Cho, Youngjin; Cho, Daehwan; Park, Jay Hoon; Frey, Margaret W.; Ober, Christopher K.; Joo, Yong Lak

2012-01-01

as KB) and fabricated amphiphilic nanofibers by electrospinning of solutions prepared by mixing the KB with poly(lactic acid) (PLA) polymer. The resulting fibers with amphiphilic polymer groups exhibited superior antifouling performance to the fibers

Stimuli Responsive Amphiphilic Assemblies

Science.gov (United States)

2013-11-18

Enzyme- Sensitive, Amphiphilic- Dendrimer -Based Nanoparticles through Photochemical Crosslinking, Chemistry - A European Journal, (10 2011): 0. doi...17, 2012 (Organizers: R. P. Singh) 8th International Dendrimer Symposium (IDS-8), Madrid, Spain, June 23-27, 2013 (Organizers: Dr. M’Angeles...investigate the pH-induced changes in surface properties. Nanocarriers that can be effectively transported across cellular membranes have potential in a

Temperature-Induced, Selective Assembly of Supramolecular Colloids in Water

NARCIS (Netherlands)

Van Ravensteijn, Bas G.P.; Vilanova, Neus; De Feijter, Isja; Kegel, Willem K.; Voets, Ilja K.

2017-01-01

In this article, we report the synthesis and physical characterization of colloidal polystyrene particles that carry water-soluble supramolecular N,N′,N″,-trialkyl-benzene-1,3,5-tricarboxamides (BTAs) on their surface. These molecules are known to assemble into one-dimensional supramolecular

Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion

Directory of Open Access Journals (Sweden)

Zhen Wang

2016-11-01

Full Text Available Pickering emulsions with the use of particles as emulsifiers have been extensively used in scientific research and industrial production due to their edge in biocompatibility and stability compared with traditional emulsions. The control over Pickering emulsion stability and type plays a significant role in these applications. Among the present methods to build controllable Pickering emulsions, tuning the amphiphilicity of particles is comparatively effective and has attracted enormous attention. In this review, we highlight some recent advances in tuning the amphiphilicity of particles for controlling the stability and type of Pickering emulsions. The amphiphilicity of three types of particles including rigid particles, soft particles, and Janus particles are tailored by means of different mechanisms and discussed here in detail. The stabilization-destabilization interconversion and phase inversion of Pickering emulsions have been successfully achieved by changing the surface properties of these particles. This article provides a comprehensive review of controllable Pickering emulsions, which is expected to stimulate inspiration for designing and preparing novel Pickering emulsions, and ultimately directing the preparation of functional materials.

Effects of perfluorinated amphiphiles on backward swimming in Paramecium caudatum

International Nuclear Information System (INIS)

Matsubara, Eriko; Harada, Kouji; Inoue, Kayoko; Koizumi, Akio

2006-01-01

PFOS and PFOA are ubiquitous contaminants in the environment. We investigated the effects of fluorochemicals on calcium currents in Paramecium caudatum using its behavioral changes. Negatively charged amphiphiles prolonged backward swimming (BWS) of Paramecium. PFOS significantly prolonged BWS, while PFOA was less potent (EC 5 : 29.8 ± 4.1 and 424.1 ± 124.0 μM, respectively). The BWS prolongation was blocked by cadmium, indicating that the cellular calcium conductance had been modified. The positively charged amphiphile FOSAPrTMA shortened BWS (EC 5 : 19.1 ± 17.3). Nonionic amphiphiles did not affect BWS. The longer-chain perfluorinated carboxylates PFNA and PFDA were more potent than PFOA (EC 5 : 98.7 ± 20.1 and 60.4 ± 10.1 μM, respectively). However, 1,8-perfluorooctanedioic acid and 1,10-perfluorodecanedioic acid did not prolong BWS. The critical micelle concentration (CMC) and BWS prolongation for negatively charged amphiphiles showed a clear correlation (r 2 = 0.8008, p < 0.001). In summary, several perfluorochemicals and PFOS and PFOA had similar effects in Paramecium, while chain length, CMC, and electric charge were major determinants of BWS duration

Hemifluorinated maltose-neopentyl glycol (HF-MNG) amphiphiles for membrane protein stabilisation.

Science.gov (United States)

Cho, Kyung Ho; Byrne, Bernadette; Chae, Pil Seok

2013-03-04

SOAP OPERA: Fluorinated amphiphile F4-MNG confers greater stability on Rhodobacter capsulatus superassembly relative to conventional detergents and nonfluorinated MNGs. Such amphiphiles are attractive as tools for membrane science because of their ease of preparation and structure variation. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stable Vesicles Composed of Mono- or Dicarboxylic Fatty Acids and Trimethylammonium Amphiphiles

DEFF Research Database (Denmark)

Caschera, Filippo; Bernardino de la Serna, Jorge; Löffler, Philipp M. G.

2011-01-01

shown to be more stable than those formed by pure fatty acids. Those containing bola-amphiphile even showed encapsulation of a small hydrophilic solute (8-hydroxypyrene-1,3,6-trisulfonic-acid) suggesting a denser packing of the amphiphiles. Compression and kinetics analysis of monolayers composed...... of these amphiphiles mixtures at the air/water interface suggest that the stabilization of the structures can be attributed to two main interactions between headgroups, predominantly the formation of hydrogen bonds between protonated and deprotonated acids and then the additional electrostatic interactions between...

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).

A New Class of Amphiphiles Bearing Rigid Hydrophobic Groups for Solubilization and Stabilization of Membrane Proteins

DEFF Research Database (Denmark)

Chae, Pil Seok; Rasmussen, Søren G F; Rana, Rohini R

2012-01-01

Non-traditional amphiphiles: Conferring aqueous solubility on membrane proteins generally requires the use of a detergent or other amphiphilic agent. A new class of amphiphiles was synthesized, based on steroidal lipophilic groups, and evaluated with several membrane proteins. The results show th...... that the new amphiphile, "glyco-diosgenin" (GDN; see figure), confers enhanced stability to a variety of membrane proteins in solution relative to popular conventional detergents, such as dodecylmaltoside (DDM)....

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.

Development of biocompatible glycodynameric hydrogels joining two natural motifs by dynamic constitutional chemistry.

Science.gov (United States)

Marin, Luminita; Ailincai, Daniela; Morariu, Simona; Tartau-Mititelu, Liliana

2017-08-15

The paper focusses on the synthesis of novel hydrogels by joining natural biodegradable compounds with the aim to achieve biocompatible materials for bio related applications. The hydrogels were prepared from chitosan and citral by constitutional dynamic chemistry, incorporating both molecular and supramolecular dynamic features. The hydrophobic flexible citral has been reversible immobilized onto the hydrophilic chitosan backbone via imine bonds to form amphiphilic glycodynamers, which further self-ordered through supramolecular interactions into a 3D-network of biodynameric hydrogel. The synthetic pathway has been demonstrated by NMR and FTIR spectroscopy, X-ray diffraction and polarized light microscopy. Studies of the hydrogel morphology revealed a 3D porous microstructure, whose pores size correlated with the crosslinking degree. Rheological investigations evidenced high elasticity, thermo-responsiveness and thixotropic behavior. As a proof of the concept, the hydrogels proved in vivo biocompatibility on laboratory mice. The paper successfully implements the constitutional dynamic chemistry in generation of chitosan high performance hydrogels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Supramolecular fluorene based materials

NARCIS (Netherlands)

Abbel, R.J.

2008-01-01

This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical

Amphiphile-induced heart muscle-cell (myocyte) injury: effects of intracellular fatty acid overload.

Science.gov (United States)

Janero, D R; Burghardt, C; Feldman, D

1988-10-01

Lipid amphiphile toxicity may be an important contributor to myocardial injury, especially during ischemia/reperfusion. In order to investigate directly the potential biochemical and metabolic effects of amphiphile overload on the functioning heart muscle cell (myocyte), a novel model of nonesterified fatty acid (NEFA)-induced myocyte damage has been defined. The model uses intact, beating neonatal rat myocytes in primary monolayer culture as a study object and 5-(tetradecyloxy)-2-furoic acid (TOFA) as a nonmetabolizable fatty acid. Myocytes incubated with TOFA accumulated it as NEFA, and the consequent NEFA amphiphile overload elicited a variety of cellular defects (including decreased beating rate, depletion of high-energy stores and glycogen pools, and breakdown of myocyte membrane phospholipid) and culminated in cell death. The amphiphile-induced cellular pathology could be reversed by removing TOFA from the culture medium, which resulted in intracellular TOFA "wash-out." Although the development and severity of amphiphile-induced myocyte injury could be correlated with both the intracellular TOFA/NEFA content (i.e., the level of TOFA to which the cells were exposed) and the duration of this exposure, removal of amphiphile overload did not inevitably lead to myocyte recovery. TOFA had adverse effects on myocyte mitochondrial function in situ (decoupling of oxidative phosphorylation, impairing respiratory control) and on myocyte oxidative catabolism (transiently increasing fatty acid beta oxidation, citric acid cycle flux, and glucose oxidation). The amphiphile-induced bioenergetic abnormalities appeared to constitute a state of "metabolic anoxia" underlying the progression of myocyte injury to cell death. This anoxic state could be ameliorated to some extent, but not prevented, by carbohydrate catabolism.

From supramolecular polymers to multi-component biomaterials.

Science.gov (United States)

Goor, Olga J G M; Hendrikse, Simone I S; Dankers, Patricia Y W; Meijer, E W

2017-10-30

The most striking and general property of the biological fibrous architectures in the extracellular matrix (ECM) is the strong and directional interaction between biologically active protein subunits. These fibers display rich dynamic behavior without losing their architectural integrity. The complexity of the ECM taking care of many essential properties has inspired synthetic chemists to mimic these properties in artificial one-dimensional fibrous structures with the aim to arrive at multi-component biomaterials. Due to the dynamic character required for interaction with natural tissue, supramolecular biomaterials are promising candidates for regenerative medicine. Depending on the application area, and thereby the design criteria of these multi-component fibrous biomaterials, they are used as elastomeric materials or hydrogel systems. Elastomeric materials are designed to have load bearing properties whereas hydrogels are proposed to support in vitro cell culture. Although the chemical structures and systems designed and studied today are rather simple compared to the complexity of the ECM, the first examples of these functional supramolecular biomaterials reaching the clinic have been reported. The basic concept of many of these supramolecular biomaterials is based on their ability to adapt to cell behavior as a result of dynamic non-covalent interactions. In this review, we show the translation of one-dimensional supramolecular polymers into multi-component functional biomaterials for regenerative medicine applications.

Controllable Self-Assembly of Amphiphilic Zwitterionic PBI Towards Tunable Surface Wettability of the Nanostructures.

Science.gov (United States)

Ye, Yong; Lü, Baozhong; Cheng, Wenyu; Wu, Zhen; Wei, Jie; Yin, Meizhen

2017-05-04

Amphiphilic molecules have received wide attention as they possess both hydrophobic and hydrophilic properties, and can form diverse nanostructures in selective solvents. Herein, we report an asymmetric amphiphilic zwitterionic perylene bisimide (AZP) with an octyl chain and a zwitterionic group on the opposite imide positions of perylene tetracarboxylic dianhydride. The controllable nanostructures of AZP with tunable hydrophilic/hydrophobic surface have been investigated through solvent-dependent amphiphilic self-assembly as confirmed by SEM, TEM, and contact angle measurements. The planar perylene core of AZP contributes to strong π-π stacking, while the amphiphilic balance of asymmetric AZP adjusts the self-assembly property. Additionally, due to intermolecular π-π stacking and solvent-solute interactions, AZP could self-assemble into hydrophilic microtubes in a polar solvent (acetone) and hydrophobic nanofibers in an apolar solvent (hexane). This facile method provides a new pathway for controlling the surface properties based on an asymmetric amphiphilic zwitterionic perylene bisimide. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure-directing star-shaped block copolymers: supramolecular vesicles for the delivery of anticancer drugs.

Science.gov (United States)

Yang, Chuan; Liu, Shao Qiong; Venkataraman, Shrinivas; Gao, Shu Jun; Ke, Xiyu; Chia, Xin Tian; Hedrick, James L; Yang, Yi Yan

2015-06-28

Amphiphilic polycarbonate/PEG copolymer with a star-like architecture was designed to facilitate a unique supramolecular transformation of micelles to vesicles in aqueous solution for the efficient delivery of anticancer drugs. The star-shaped amphipilic block copolymer was synthesized by initiating the ring-opening polymerization of trimethylene carbonate (TMC) from methyl cholate through a combination of metal-free organo-catalytic living ring-opening polymerization and post-polymerization chain-end derivatization strategies. Subsequently, the self-assembly of the star-like polymer in aqueous solution into nanosized vesicles for anti-cancer drug delivery was studied. DOX was physically encapsulated into vesicles by dialysis and drug loading level was significant (22.5% in weight) for DOX. Importantly, DOX-loaded nanoparticles self-assembled from the star-like copolymer exhibited greater kinetic stability and higher DOX loading capacity than micelles prepared from cholesterol-initiated diblock analogue. The advantageous disparity is believed to be due to the transformation of micelles (diblock copolymer) to vesicles (star-like block copolymer) that possess greater core space for drug loading as well as the ability of such supramolecular structures to encapsulate DOX. DOX-loaded vesicles effectively inhibited the proliferation of 4T1, MDA-MB-231 and BT-474 cells, with IC50 values of 10, 1.5 and 1.0mg/L, respectively. DOX-loaded vesicles injected into 4T1 tumor-bearing mice exhibited enhanced accumulation in tumor tissue due to the enhanced permeation and retention (EPR) effect. Importantly, DOX-loaded vesicles demonstrated greater tumor growth inhibition than free DOX without causing significant body weight loss or cardiotoxicity. The unique ability of the star-like copolymer emanating from the methyl cholate core provided the requisite modification in the block copolymer interfacial curvature to generate vesicles of high loading capacity for DOX with significant

Microfluidics-assisted generation of stimuli-responsive hydrogels based on alginates incorporated with thermo-responsive and amphiphilic polymers as novel biomaterials.

Science.gov (United States)

Karakasyan, C; Mathos, J; Lack, S; Davy, J; Marquis, M; Renard, D

2015-11-01

We used a droplet-based microfluidics technique to produce monodisperse responsive alginate-block-polyetheramine copolymer microgels. The polyetheramine group (PEA), corresponding to a propylene oxide /ethylene oxide ratio (PO/EO) of 29/6 (Jeffamine(®) M2005), was condensed, via the amine link, to alginates with various mannuronic/guluronic acids ratios and using two alginate:jeffamine mass ratios. The size of the grafted-alginate microgels varied from 60 to 80 μm depending on the type of alginate used and the degree of substitution. The droplet-based microfluidics technique offered exquisite control of both the dimension and physical chemical properties of the grafted-alginate microgels. These microgels were therefore comparable to isolated grafted-alginate chains in retaining both their amphiphilic and thermo-sensitive properties. Amphiphilicity was demonstrated at the oil-water interface where grafted-alginate microgels were found to decrease interfacial tension by ∼ 50%. The thermo-sensitivity of microgels was clearly demonstrated and a 10 to 20% reduction in size between was evidenced on increasing the temperature above the lower critical solution temperature (TLCST) of Jeffamine. In addition, the reversibility of thermo-sensitivity was demonstrated by studying the oil-water affinity of microgels with temperature after Congo red labeling. Finally, droplet-based microfluidics was found to be a good and promising tool for generating responsive biobased hydrogels for drug delivery applications and potential new colloidal stabilizers for dispersed systems such as Pickering emulsions. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Quantum-Chemical Insights into the Self-Assembly of Carbon-Based Supramolecular Complexes

Directory of Open Access Journals (Sweden)

Joaquín Calbo

2018-01-01

Full Text Available Understanding how molecular systems self-assemble to form well-organized superstructures governed by noncovalent interactions is essential in the field of supramolecular chemistry. In the nanoscience context, the self-assembly of different carbon-based nanoforms (fullerenes, carbon nanotubes and graphene with, in general, electron-donor molecular systems, has received increasing attention as a means of generating potential candidates for technological applications. In these carbon-based systems, a deep characterization of the supramolecular organization is crucial to establish an intimate relation between supramolecular structure and functionality. Detailed structural information on the self-assembly of these carbon-based nanoforms is however not always accessible from experimental techniques. In this regard, quantum chemistry has demonstrated to be key to gain a deep insight into the supramolecular organization of molecular systems of high interest. In this review, we intend to highlight the fundamental role that quantum-chemical calculations can play to understand the supramolecular self-assembly of carbon-based nanoforms through a limited selection of supramolecular assemblies involving fullerene, fullerene fragments, nanotubes and graphene with several electron-rich π-conjugated systems.

Towards supramolecular engineering of functional nanomaterials: pre-programming multi-component 2D self-assembly at solid-liquid interfaces.

Science.gov (United States)

Ciesielski, Artur; Palma, Carlos-Andres; Bonini, Massimo; Samorì, Paolo

2010-08-24

Materials with a pre-programmed order at the supramolecular level can be engineered with a sub-nanometer precision making use of reversible non- covalent interactions. The intrinsic ability of supramolecular materials to recognize and exchange their constituents makes them constitutionally dynamic materials. The tailoring of the materials properties relies on the full control over the self-assembly behavior of molecular modules exposing recognition sites and incorporating functional units. In this review we focus on three classes of weak-interactions to form complex 2D architectures starting from properly designed molecular modules: van der Waals, metallo-ligand and hydrogen bonding. Scanning tunneling microscopy studies will provide evidence with a sub-nanometer resolution, on the formation of responsive multicomponent architectures with controlled geometries and properties. Such endeavor enriches the scientist capability of generating more and more complex smart materials featuring controlled functions and unprecedented properties.

Magnetic Amphiphilic Composites Applied for the Treatment of Biodiesel Wastewaters

Directory of Open Access Journals (Sweden)

Bruno R. S. Lemos

2012-05-01

Full Text Available In this work, new magnetic amphiphilic composites were prepared by chemical vapor deposition with ethanol on the surface of hydrophilic natural chrysotile matrix containing Fe catalyst. XRD, Raman, Mössbauer and SEM analyses suggest the formation of a complex nanostructured material composed of hydrophobic carbon nanotubes/nanofibers grown on the hydrophilic surface of the MgSi fiber mineral and the presence of Fe metallic nanoparticles coated by carbon. These nanostructured particles show amphiphilic properties and interact very well with both oil and aqueous phases. When added to emulsions the amphiphilic particles locate on the oil/water interface and, under a magnetic field, the oil droplets collapsed leading to the separation of the aqueous and oil phases. Preliminary work showed excellent results on the use of these particles to break wastewater emulsions in the biodiesel process.

Dynamic and bio-orthogonal protein assembly along a supramolecular polymer

NARCIS (Netherlands)

Petkau - Milroy, K.; Uhlenheuer, D.A.; Spiering, A.J.H.; Vekemans, J.A.J.M.; Brunsveld, L.

2013-01-01

Dynamic protein assembly along supramolecular columnar polymers has been achieved through the site-specific covalent attachment of different SNAP-tag fusion proteins to self-assembled benzylguanine-decorated discotics. The self-assembly of monovalent discotics into supramolecular polymers creates a

Toward a versatile toolbox for cucurbit[n]uril-based supramolecular hydrogel networks through in situ polymerization.

Science.gov (United States)

Liu, Ji; Soo Yun Tan, Cindy; Lan, Yang; Scherman, Oren A

2017-09-15

The success of exploiting cucurbit[ n ]uril (CB[ n ])-based molecular recognition in self-assembled systems has sparked a tremendous interest in polymer and materials chemistry. In this study, polymerization in the presence of host-guest complexes is applied as a modular synthetic approach toward a diverse set of CB[8]-based supramolecular hydrogels with desirable properties, such as mechanical strength, toughness, energy dissipation, self-healing, and shear-thinning. A range of vinyl monomers, including acrylamide-, acrylate-, and imidazolium-based hydrophilic monomers, could be easily incorporated as the polymer backbones, leading to a library of CB[8] hydrogel networks. This versatile strategy explores new horizons for the construction of supramolecular hydrogel networks and materials with emergent properties in wearable and self-healable electronic devices, sensors, and structural biomaterials. © 2017 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3105-3109.

Consequences of chirality on the dynamics of a water-soluble supramolecular polymer.

Science.gov (United States)

Baker, Matthew B; Albertazzi, Lorenzo; Voets, Ilja K; Leenders, Christianus M A; Palmans, Anja R A; Pavan, Giovanni M; Meijer, E W

2015-02-20

The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers: one with and one without a stereogenic methyl. Initially aiming simply to understand the molecular behaviour of these systems in water, we find that while the fibres may look identical, the introduction of homochirality imparts a higher level of internal order to the supramolecular polymer. Although this increased order does not seem to affect the basic dimensions of the supramolecular fibres, the equilibrium dynamics of the polymers differ by almost an order of magnitude. This report represents the first observation of a structure/property relationship with regard to equilibrium dynamics in water-soluble supramolecular polymers.

Consequences of chirality on the dynamics of a water-soluble supramolecular polymer

Science.gov (United States)

Baker, Matthew B.; Albertazzi, Lorenzo; Voets, Ilja K.; Leenders, Christianus M. A.; Palmans, Anja R. A.; Pavan, Giovanni M.; Meijer, E. W.

2015-02-01

The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers: one with and one without a stereogenic methyl. Initially aiming simply to understand the molecular behaviour of these systems in water, we find that while the fibres may look identical, the introduction of homochirality imparts a higher level of internal order to the supramolecular polymer. Although this increased order does not seem to affect the basic dimensions of the supramolecular fibres, the equilibrium dynamics of the polymers differ by almost an order of magnitude. This report represents the first observation of a structure/property relationship with regard to equilibrium dynamics in water-soluble supramolecular polymers.

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.

Asymmetric and symmetric bolaform supra-amphiphiles: formation of imine bond influenced by aggregation.

Science.gov (United States)

Wang, Guangtong; Wu, Guanglu; Wang, Zhiqiang; Zhang, Xi

2014-02-18

A series of bolaform supra-amphilphiles with different symmetries were fabricated through dynamic benzoic imine bond formation. The pH dependence of imine formations of these supra-amphiphiles were characterazied. We found that the extent of the imine formation of these supra-amphiphies were different. The supra-amphiphiles with a poorer symmetry always exhibited a lower imine formation at a given pH. Therefore, the varied extent of imine bond formation indicate the different aggregations of these supra-amphilphiles, which are controlled by the molecular symmetry of the supra-amphiphiles.

Anti-Biofouling Properties of Comblike Block Copolymers with Amphiphilic Side Chains

International Nuclear Information System (INIS)

Krishnan, S.; Ayothi, R.; Hexemer, A.; Finlay, J.; Sohn, K.; Perry, R.; Ober, C.; Kramer, E.; Callow, M.

2006-01-01

Surfaces of novel block copolymers with amphiphilic side chains were studied for their ability to influence the adhesion of marine organisms. The surface-active polymer, obtained by grafting fluorinated molecules with hydrophobic and hydrophilic blocks to a block copolymer precursor, showed interesting bioadhesion properties. Two different algal species, one of which adhered strongly to hydrophobic surfaces, and the other, to hydrophilic surfaces, showed notably weak adhesion to the amphiphilic surfaces. Both organisms are known to secrete adhesive macromolecules, with apparently different wetting characteristics, to attach to underwater surfaces. The ability of the amphiphilic surface to undergo an environment-dependent transformation in surface chemistry when in contact with the extracellular polymeric substances is a possible reason for its antifouling nature. Near-edge X-ray absorption fine structure spectroscopy (NEXAFS) was used, in a new approach based on angle-resolved X-ray photoelectron spectroscopy (XPS), to determine the variation in chemical composition within the top few nanometers of the surface and also to study the surface segregation of the amphiphilic block. A mathematical model to extract depth-profile information from the normalized NEXAFS partial electron yield is developed

Fabrication of novel biodegradable porous bone scaffolds based on amphiphilic hydroxyapatite nanorods

Energy Technology Data Exchange (ETDEWEB)

Zheng, Xiaoyan; Hui, Junfeng [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China); Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069, Shaanxi (China); Li, Hui; Zhu, Chenhui [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China); Hua, Xiufu, E-mail: hua_xiufu@163.com [Department of Scientific Research and Development, Tsinghua University, Beijing 100084 (China); Ma, Haixia, E-mail: mahx@nwu.edu.cn [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry & Materials Science, Northwest University, Xi' an 710069, Shaanxi (China); Fan, Daidi, E-mail: fandaidi@nwu.edu.cn [Shaanxi Key Laboratory of Degradable Biomedical Materials, Shaanxi R& D Center of Biomaterials and Fermentation Engineering, School of Chemical and Engineering, Northwest University, Xi' an 710069, Shaanxi, PR China2 (China)

2017-06-01

This paper describes a new synthetic strategy and biological application for novel amphiphilic hydroxyapatite (HAp) nanorods. The prepared HAp nanorods were able to be dispersed in water, ethyl alcohol and cyclohexane. The co-anchoring of the multidentate ligands of PEG 20000 and hydrophobic oleic acid (OA) on the rods' surfaces endowed them with excellent amphibious properties. Utilizing amphiphilic HAp nanorods with excellent biocompatibility as the inorganic phase, human-like collagen (HLC) as the organic phase and natural genipin as the cross-linker, optimal HLC/HAp porous scaffolds (HLC: HAp = 1:4, w/w) were fabricated. The compression stress and three-point bending strength of the scaffolds with pore diameters of 150 to 200 μm reached approximately 3.4 MPa and 5.4 MPa, respectively, and their porosity was 77.35 ± 3.75%. Cytological tests showed that HLC/HAp scaffolds could contribute to cell proliferation and differentiation. The results indicated that these novel amphiphilic HAp nanorods can be expected to become recognized as an excellent inorganic material for the porous scaffolds used in repairing bone and related applications. - Highlights: • A simple and effective hydrothermal method was developed for preparing uniform HAp nanorods with amphiphilic surfaces. • The synthesized amphiphilic HAp nanorods could be dispersed in water, ethyl alcohol or cyclohexane. • The prepared HLC/HAp porous scaffolds had good mechanical properties, biocompatibility and osteoconductive etc.

Fabrication of novel biodegradable porous bone scaffolds based on amphiphilic hydroxyapatite nanorods

International Nuclear Information System (INIS)

Zheng, Xiaoyan; Hui, Junfeng; Li, Hui; Zhu, Chenhui; Hua, Xiufu; Ma, Haixia; Fan, Daidi

2017-01-01

This paper describes a new synthetic strategy and biological application for novel amphiphilic hydroxyapatite (HAp) nanorods. The prepared HAp nanorods were able to be dispersed in water, ethyl alcohol and cyclohexane. The co-anchoring of the multidentate ligands of PEG 20000 and hydrophobic oleic acid (OA) on the rods' surfaces endowed them with excellent amphibious properties. Utilizing amphiphilic HAp nanorods with excellent biocompatibility as the inorganic phase, human-like collagen (HLC) as the organic phase and natural genipin as the cross-linker, optimal HLC/HAp porous scaffolds (HLC: HAp = 1:4, w/w) were fabricated. The compression stress and three-point bending strength of the scaffolds with pore diameters of 150 to 200 μm reached approximately 3.4 MPa and 5.4 MPa, respectively, and their porosity was 77.35 ± 3.75%. Cytological tests showed that HLC/HAp scaffolds could contribute to cell proliferation and differentiation. The results indicated that these novel amphiphilic HAp nanorods can be expected to become recognized as an excellent inorganic material for the porous scaffolds used in repairing bone and related applications. - Highlights: • A simple and effective hydrothermal method was developed for preparing uniform HAp nanorods with amphiphilic surfaces. • The synthesized amphiphilic HAp nanorods could be dispersed in water, ethyl alcohol or cyclohexane. • The prepared HLC/HAp porous scaffolds had good mechanical properties, biocompatibility and osteoconductive etc.

Sacrificial amphiphiles: Eco-friendly chemical herders as oil spill mitigation chemicals.

Science.gov (United States)

Gupta, Deeksha; Sarker, Bivas; Thadikaran, Keith; John, Vijay; Maldarelli, Charles; John, George

2015-06-01

Crude oil spills are a major threat to marine biota and the environment. When light crude oil spills on water, it forms a thin layer that is difficult to clean by any methods of oil spill response. Under these circumstances, a special type of amphiphile termed as "chemical herder" is sprayed onto the water surrounding the spilled oil. The amphiphile forms a monomolecular layer on the water surface, reducing the air-sea surface tension and causing the oil slick to retract into a thick mass that can be burnt in situ. The current best-known chemical herders are chemically stable and nonbiodegradable, and hence remain in the marine ecosystem for years. We architect an eco-friendly, sacrificial, and effective green herder derived from the plant-based small-molecule phytol, which is abundant in the marine environment, as an alternative to the current chemical herders. Phytol consists of a regularly branched chain of isoprene units that form the hydrophobe of the amphiphile; the chain is esterified to cationic groups to form the polar group. The ester linkage is proximal to an allyl bond in phytol, which facilitates the hydrolysis of the amphiphile after adsorption to the sea surface into the phytol hydrophobic tail, which along with the unhydrolyzed herder, remains on the surface to maintain herding action, and the cationic group, which dissolves into the water column. Eventual degradation of the phytol tail and dilution of the cation make these sacrificial amphiphiles eco-friendly. The herding behavior of phytol-based amphiphiles is evaluated as a function of time, temperature, and water salinity to examine their versatility under different conditions, ranging from ice-cold water to hot water. The green chemical herder retracted oil slicks by up to ~500, 700, and 2500% at 5°, 20°, and 35°C, respectively, during the first 10 min of the experiment, which is on a par with the current best chemical herders in practice.

Phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles: Specific characteristics of the condensed phases.

Science.gov (United States)

Vollhardt, D

2015-08-01

For understanding the role of amide containing amphiphiles in inherently complex biological processes, monolayers at the air-water interface are used as simple biomimetic model systems. The specific characteristics of the condensed phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles are surveyed to highlight the effect of the chemical structure of the amide amphiphiles on the interfacial interactions in model monolayers. The mesoscopic topography and/or two-dimensional lattice structures of selected amino acid amphiphiles, amphiphilic N-alkylaldonamide, amide amphiphiles with specific tailored headgroups, such as amide amphiphiles based on derivatized ethanolamine, e.g. acylethanolamines (NAEs) and N-,O-diacylethanolamines (DAEs) are presented. Special attention is devoted the dominance of N,O-diacylated ethanolamine in mixed amphiphilic acid amide monolayers. The evidence that a first order phase transition can occur in adsorption layers and that condensed phase domains of mesoscopic scale can be formed in adsorption layers was first obtained on the basis of the experimental characteristics of a tailored amide amphiphile. New thermodynamic and kinetic concepts for the theoretical description of the characteristics of amide amphiphile's monolayers were developed. In particular, the equation of state for Langmuir monolayers generalized for the case that one, two or more phase transitions occur, and the new theory for phase transition in adsorbed monolayers are experimentally confirmed at first by amide amphiphile monolayers. Despite the significant progress made towards the understanding the model systems, these model studies are still limited to transfer the gained knowledge to biological systems where the fundamental physical principles are operative in the same way. The study of biomimetic systems, as described in this review, is only a first step in this direction. Copyright © 2014 Elsevier B.V. All rights reserved.

Amphiphilic cationic peptides mediate cell adhesion to plastic surfaces.

Science.gov (United States)

Rideout, D C; Lambert, M; Kendall, D A; Moe, G R; Osterman, D G; Tao, H P; Weinstein, I B; Kaiser, E T

1985-09-01

Four amphiphilic peptides, each with net charges of +2 or more at neutrality and molecular weights under 4 kilodaltons, were found to mediate the adhesion of normal rat kidney fibroblasts to polystyrene surfaces. Two of these peptides, a model for calcitonin (peptide 1, MCT) and melittin (peptide 2, MEL), form amphiphilic alpha-helical structures at aqueous/nonpolar interfaces. The other two, a luteinizing hormone-releasing hormone model (peptide 3, LHM) and a platelet factor model (peptide 4, MPF) form beta-strand structures in amphiphilic environments. Although it contains only 10 residues, LHM mediated adhesion to surfaces coated with solutions containing as little as 10 pmoles/ml of peptide. All four of these peptides were capable of forming monolayers at air-buffer interfaces with collapse pressures greater than 20 dynes/cm. None of these four peptides contains the tetrapeptide sequence Arg-Gly-Asp-Ser, which has been associated with fibronectin-mediated cell adhesion. Ten polypeptides that also lacked the sequence Arg-Gly-Asp-Ser but were nonamphiphilic and/or had net charges less than +2 at neutrality were all incapable of mediating cell adhesion (Pierschbacher and Ruoslahti, 1984). The morphologies of NRK cells spread on polystyrene coated with peptide LHM resemble the morphologies on fibronectin-coated surfaces, whereas cells spread on surfaces coated with MCT or MEL exhibit strikingly different morphologies. The adhesiveness of MCT, MEL, LHM, and MPF implies that many amphiphilic cationic peptides could prove useful as well defined adhesive substrata for cell culture and for studies of the mechanism of cell adhesion.

Maltose-neopentyl glycol (MNG) amphiphiles for solubilization, stabilization and crystallization of membrane proteins

DEFF Research Database (Denmark)

Chae, Pil Seok; Rasmussen, Søren G F; Rana, Rohini R

2010-01-01

proteins remain difficult to study owing to a lack of suitable detergents. We introduce a class of amphiphiles, each built around a central quaternary carbon atom derived from neopentyl glycol, with hydrophilic groups derived from maltose. Representatives of this maltose-neopentyl glycol (MNG) amphiphile...

Dielectric properties of supramolecular ionic structures obtained from multifunctional carboxylic acids and amines

DEFF Research Database (Denmark)

Gonzalez, Lidia; Yu, Liyun; Hvilsted, Søren

2014-01-01

The dielectric properties of several supramolecular ionic polymers and networks, linked by the ammonium salts of hexamethylene diamine (HMDA), tris(2-aminoethyl)amine (TAEA), poly(propylene imine) (PPI) dendrimers and two short bis carboxymethyl ether-terminated poly(ethylene glycol)s (Di......COOH-PEG), are reported in this paper. All supramolecular ionic polymers and networks exhibit very high relative dielectric permittivities ( 3 0 )( 10 2 – 10 6 ) at low frequencies, and signi fi cantly lower values (from 1 up to 26) at high frequencies. Additionally, the dielectric properties of supramolecular ionic......), are investigated. Here the relative dielectric permittivities of the supramolecular ionic structures formed with the multifunctional carboxylic acids were lower than those from the supramolecular ionic structures formed with the two carboxymethyl ether-terminated poly(ethylene glycol)s....

Amphiphilic copolymers for fouling-release coatings

DEFF Research Database (Denmark)

Noguer, Albert Camós; Olsen, Stefan Møller; Hvilsted, Søren

of the coatings [9,10,11]. This work shows the effect of an amphiphilic copolymer that induces hydrophilicity on the surface of the silicone-based fouling release coatings. The behaviour of these copolymers within the coating upon immersion and the interaction of these surface-active additives with other...

Solid-phase based synthesis of ureidopyrimidinone-peptide conjugates for supramolecular biomaterials

NARCIS (Netherlands)

Feijter, de I.; Goor, O.J.G.M.; Hendrikse, S.I.S.; Comellas Aragones, M.; Sontjens, S.H.M.; Zaccaria, S.; Fransen, P.P.K.H.; Peeters, J.W.; Milroy, L.G.; Dankers, P.Y.W.

2015-01-01

Supramolecular polymers have shown to be powerful scaffolds for tissue engineering applications. Supramolecular biomaterials functionalized with ureidopyrimidinone (UPy) moieties, which dimerize via quadruple hydrogen-bond formation, are eminently suitable for this purpose. The conjugation of the

Application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry

International Nuclear Information System (INIS)

Shen Xinghai; Chen Qingde; Gao Hongcheng

2008-01-01

Supramolecular chemistry, one of the front fields in 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. This article focuses on the application of the principle of supramolecular chemistry in the fields of radiochemistry and radiation chemistry. The following aspects are concerned: (1) the recent progress of supramolecular chemistry; (2) the application of the principle of supramolecular chemistry and the functions of supramolecular system, i.e., recognition, assembly and translocation, in the extraction of nuclides; (3) the application of microemulsion, ionic imprinted polymers, ionic liquids and cloud point extraction in the enrichment of nuclides; (4) the radiation effect of supramolecular systems. (authors)

From supramolecular electrochemistry to molecular-level devices

Energy Technology Data Exchange (ETDEWEB)

Credi, Alberto; Ferrer Ribera, Belen; Venturi, Margherita

2004-09-15

Supramolecular (multi-component) systems can perform complex functions which result from the cooperation of actions performed by suitably selected molecular components. Looking at supramolecular systems, from the viewpoint of the functions, shows that the concept of macroscopic device can be extended to molecular level. Nature exploits very complex molecular-level devices to substain life, and, in the last twenty years, the development of supramolecular chemistry has allowed the construction of simple molecular-level devices, that are of interest not only for basic research, but also for the growth of nanoscience and nanotechnology. Molecular-level devices operate via electronic and/or nuclear rearrangements, and like macroscopic devices, they need energy to operate and signals to communicate with the operator. Electrochemistry can provide the answer to this dual requirement, since electrons/holes, besides supplying the energy needed to make a devices work, can also be useful to 'read' the state of the system and thus to control and monitor the operation of the device. In this article, some examples of molecular-level devices investigated in our laboratory will be reviewed.

Self-Assembling Peptide Amphiphiles for Therapeutic Delivery of Proteins, Drugs, and Stem Cells

Science.gov (United States)

Lee, Sungsoo Seth

Biomaterials are used to help regenerate or replace the structure and function of damaged tissues. In order to elicit desired therapeutic responses in vivo, biomaterials are often functionalized with bioactive agents, such as growth factors, small molecule drugs, or even stem cells. Therefore, the strategies used to incorporate these bioactive agents in the microstructures and nanostructures of biomaterials can strongly influence the their therapeutic efficacy. Using self-assembling peptide amphiphiles (PAs), this work has investigated supramolecular nanostructures with improved interaction with three types of therapeutic agents: bone morphogenetic protein 2 (BMP-2) which promotes osteogenic differentiation and bone growth, anti-inflammatory drug naproxen which is used to treat osteo- and rheumatoid arthritis, and neural stem cells that could differentiate into neurons to treat neurodegenerative diseases. For BMP-2 delivery, two specific systems were investigated with affinity for BMP-2: 1) heparin-binding nanofibers that display the natural ligand of the osteogenic protein, and 2) nanofibers that display a synthetic peptide ligand discovered in our laboratory through phage display to directly bind BMP-2. Both systems promoted enhanced osteoblast differentiation of pluripotent C2C12 cells and augmented bone regeneration in two in vivo models, a rat critical-size femur defect model and spinal arthrodesis model. The thesis also describes the use of PA nanofibers to improve the delivery of the anti-inflammatory drug naproxen. To promote a controlled release, naproxen was chemically conjugated to the nanofiber surface via an ester bond that would only be cleaved by esterases, which are enzymes found naturally in the body. In the absence of esterases, the naproxen remained conjugated to the nanofibers and was non-bioactive. On the other hand, in the presence of esterases, naproxen was slowly released and inhibited cyclooxygenase-2 (COX-2) activity, an enzyme responsible

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

Energy Technology Data Exchange (ETDEWEB)

Li Jianhua, E-mail: jhli_2005@163.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China); Zhang Qiqing, E-mail: zhangqiq@126.com [Institute of Biomedical and Pharmaceutical Technology and College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350001 (China) and Institute of Biomedical Engineering, Chinese Academy of Medical Science, Peking Union Medical College, Tianjin 300192 (China)

2012-06-15

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

Improved surface property of PVDF membrane with amphiphilic zwitterionic copolymer as membrane additive

International Nuclear Information System (INIS)

Li Jianhua; Li Mizi; Miao Jing; Wang Jiabin; Shao Xisheng; Zhang Qiqing

2012-01-01

An attempt to improve hydrophilicity and anti-fouling properties of PVDF membranes, a novel amphiphilic zwitterionic copolymer poly(vinylidene fluoride)-graft-poly(sulfobetaine methacrylate) (PVDF-g-PSBMA) was firstly synthesized by atom transfer radical polymerization (ATRP) and used as amphiphilic copolymer additive in the preparation of PVDF membranes. The PVDF-g-PSBMA/PVDF blend membranes were prepared by immersion precipitation process. Fourier transform infrared attenuated reflection spectroscopy (FTIR-ATR) and X-ray photoelectronic spectroscopy (XPS) measurements confirmed that PSBMA brushes from amphiphilic additives were preferentially segregated to membrane-coagulant interface during membrane formation. The morphology of membranes was characterized by scanning electron microscopy (SEM). Water contact angle measurements showed that the surface hydrophilicity of PVDF membranes was improved significantly with the increasing of amphiphilic copolymer PVDF-g-PSBMA in cast solution. Protein static adsorption experiment and dynamic fouling resistance experiment revealed that the surface enrichment of PSBMA brush endowed PVDF blend membrane great improvement of surface anti-fouling ability.

Revolving supramolecular chiral structures powered by light in nanomotor-doped liquid crystals

Science.gov (United States)

Orlova, Tetiana; Lancia, Federico; Loussert, Charles; Iamsaard, Supitchaya; Katsonis, Nathalie; Brasselet, Etienne

2018-04-01

Molecular machines operated by light have been recently shown to be able to produce oriented motion at the molecular scale1,2 as well as do macroscopic work when embedded in supramolecular structures3-5. However, any supramolecular movement irremediably ceases as soon as the concentration of the interconverting molecular motors or switches reaches a photo-stationary state6,7. To circumvent this limitation, researchers have typically relied on establishing oscillating illumination conditions—either by modulating the source intensity8,9 or by using bespoke illumination arrangements10-13. In contrast, here we report a supramolecular system in which the emergence of oscillating patterns is encoded at the molecular level. Our system comprises chiral liquid crystal structures that revolve continuously when illuminated, under the action of embedded light-driven molecular motors. The rotation at the supramolecular level is sustained by the diffusion of the motors away from a localized illumination area. Above a critical irradiation power, we observe a spontaneous symmetry breaking that dictates the directionality of the supramolecular rotation. The interplay between the twist of the supramolecular structure and the diffusion14 of the chiral molecular motors creates continuous, regular and unidirectional rotation of the liquid crystal structure under non-equilibrium conditions.

Star-shaped tetrathiafulvalene oligomers towards the construction of conducting supramolecular assembly.

Science.gov (United States)

Iyoda, Masahiko; Hasegawa, Masashi

2015-01-01

The construction of redox-active supramolecular assemblies based on star-shaped and radially expanded tetrathiafulvalene (TTF) oligomers with divergent and extended conjugation is summarized. Star-shaped TTF oligomers easily self-aggregate with a nanophase separation to produce supramolecular structures, and their TTF units stack face-to-face to form columnar structures using the fastener effect. Based on redox-active self-organizing supramolecular structures, conducting nanoobjects are constructed by doping of TTF oligomers with oxidants after the formation of such nanostructures. Although radical cations derived from TTF oligomers strongly interact in solution to produce a mixed-valence dimer and π-dimer, it seems to be difficult to produce nanoobjects of radical cations different from those of neutral TTF oligomers. In some cases, however, radical cations form nanostructured fibers and rods by controlling the supramolecular assembly, oxidation states, and counter anions employed.

Nanostructures and surface hydrophobicity of self-assembled thermosets involving epoxy resin and poly(2,2,2-trifluoroethyl acrylate)-block-poly(ethylene oxide) amphiphilic diblock copolymer.

Science.gov (United States)

Yi, Fangping; Zheng, Sixun; Liu, Tianxi

2009-02-19

Poly(2,2,2-trifluoroethyl acrylate)-block-poly(ethylene oxide) (PTFEA-b-PEO) amphiphilic diblock copolymer was synthesized via the reversible addition-fragmentation transfer polymerization of 2,2,2-triffluroethyl acrylate with dithiobenzoyl-terminated poly(ethylene oxide) as a chain-transfer agent. The amphiphilic diblock copolymer was incorporated into epoxy resin to prepare the nanostructured epoxy thermosets. The nanostructures were investigated by means of atomic force microscopy, small-angle X-ray scattering, and dynamic mechanical analysis. In terms of the miscibility of the subchains of the block copolymer with epoxy after and before curing reaction, it is judged that the formation of the nanostructures follows the mechanism of self-assembly. The static contact angle measurements indicate that the nanostructured thermosets containing PTFEA-b-PEO diblock copolymer displayed a significant enhancement in surface hydrophobicity as well as a reduction in surface free energy. The improvement in surface properties was ascribed to the enrichment of the fluorine-containing subchain (i.e., PTFEA block) of the amphiphilic diblock copolymer on the surface of the nanostructured thermosets, which was evidenced by surface atomic force microscopy and energy-dispersive X-ray spectroscopy.

Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

International Nuclear Information System (INIS)

Purdy Drew, Kirstin R.; Sanders, Lori K.; Culumber, Zachary W.; Zribi, Olena; Wong, Gerard C.L.

2009-01-01

It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers.

Cationic Amphiphiles Increase Activity of Aminoglycoside Antibiotic Tobramycin in the Presence of Airway Polyelectrolytes

International Nuclear Information System (INIS)

Drew, K.R.Purdy; Sanders, L.K.; Culumber, Z.W.; Zribi, O.; Wong, G.C.L.

2009-01-01

It is empirically known that anionic polyelectrolytes present in cystic fibrosis (CF) airways due to bacterial infection significantly decrease the activity of cationic antimicrobials via electrostatic binding. In this work, we use synchrotron small-angle X-ray scattering to investigate the interaction between tobramycin, an aminoglycoside antibiotic commonly administered to CF patients via inhalation, with DNA, which is found in high concentrations in the CF airway. We find that interactions between DNA and tobramycin are significantly modified by the presence of mixtures of amphiphilic molecules. We measure a hierarchy of self-assembled structures formed between tobramycin, DNA, and the amphiphile mixtures and show how interactions between these components can be controlled. Results indicate that mixtures of cationic and negative curvature amphiphiles optimized for DNA binding via charge matching and curvature matching can competitively displace bound tobramycin from DNA and thereby drastically suppress tobramycin-DNA binding and resultant antimicrobial inactivation. Growth inhibition assays confirm the increased activity of tobramycin in the presence of DNA with the addition of the amphiphiles. These results suggest that optimized cationic amphiphile solutions have the potential to enhance antimicrobial function in highly infected environments that contain increased concentrations of anionic inflammatory polymers

[Special impact of supramolecular chemistry on Chinese medicine theories].

Science.gov (United States)

He, Fu-Yuan; Zhou, Yi-Qun; Deng, Kai-Wen; Deng, Jun-Lin; Shi, Ji-Lian; Liu, Wen-Long; Yang, Yan-Tao; Tang, Yu; Liu, Zhi-Gang

2014-04-01

The paper aimed to elucidate the specific impact of supramolecular chemistry on the Chinese medicine theories (CMT) in their modernization, after had summarized up the research status of supramolecular chemistry and analyzed the possible supramolecular forms of Chinese medicine (CM), as well as considered the problems in modernization of CM theories. On comparison of the classical chemistry that delt with chemical bonds among atoms, the supramolecular chemistry was rather concerned with varietes of weak noncovalent bonds intermolecules, and reflected the macro-apparent chemical properties of each molecules, and was the most appropriate chemical theories to explain the CMT and microcosmic materials. The molecules in the human body and Chinese material medica (CMM) formed supramolecules by way of self-assembly, self-organization, self-recognition and self-replication, with themselves or with complexation, composition, chelation, inclusion, neutralization etc. Meridian and Zang-fu viscera in CMT might be a space channel structure continuously consisted of unique molecules cavity that was imprinted with the supramolecularly template inside and outside of cells, through which the molecules in CMM interacted with the meridian and Zang-fu viscera. When small molecules in human body imprinted with macromolecules in meridian and Zang-fu viscera, in other words, they migrated along within imprinting channels of meridian and Zang-fu viscera on behavior of "Qi chromatography" impulsed by the heart beat, finally showed up on macroscopic the anisotropy of tissue and organ, as described namely as visceral manifestation in Chinese medical science. When small molecules in CMM interacted with imprinting channel on meridian and Zang-fu viscera, the natural properties and efficacy regularities of CMM was reflected on macroscopic. Therefore, the special representation forms of basic CMT is based on the macroscopic expression of "Qi chromatography" abided by imprinting effect

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.

The encapsulation of an amphiphile into polystyrene microspheres of narrow size distribution

Directory of Open Access Journals (Sweden)

Pellach Michal

2011-12-01

Full Text Available Abstract Encapsulation of compounds into nano- or microsized organic particles of narrow size distribution is of increasing importance in fields of advanced imaging and diagnostic techniques and drug delivery systems. The main technology currently used for encapsulation of molecules within uniform template particles while retaining their size distribution is based on particle swelling methodology, involving penetration of emulsion droplets into the particles. The swelling method, however, is efficient for encapsulation only of hydrophobic compounds within hydrophobic template particles. In order to be encapsulated, the molecules must favor the hydrophobic phase of an organic/aqueous biphasic system, which is not easily achieved for molecules of amphiphilic character. The following work overcomes this difficulty by presenting a new method for encapsulation of amphiphilic molecules within uniform hydrophobic particles. We use hydrogen bonding of acid and base, combined with a pseudo salting out effect, for the entrapment of the amphiphile in the organic phase of a biphasic system. Following the entrapment in the organic phase, we demonstrated, using fluorescein and (antibiotic tetracycline as model molecules, that the swelling method usually used only for hydrophobes can be expanded and applied to amphiphilic molecules.

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. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diverse Supramolecular Nanofiber Networks Assembled by Functional Low-Complexity Domains.

Science.gov (United States)

An, Bolin; Wang, Xinyu; Cui, Mengkui; Gui, Xinrui; Mao, Xiuhai; Liu, Yan; Li, Ke; Chu, Cenfeng; Pu, Jiahua; Ren, Susu; Wang, Yanyi; Zhong, Guisheng; Lu, Timothy K; Liu, Cong; Zhong, Chao

2017-07-25

Self-assembling supramolecular nanofibers, common in the natural world, are of fundamental interest and technical importance to both nanotechnology and materials science. Despite important advances, synthetic nanofibers still lack the structural and functional diversity of biological molecules, and the controlled assembly of one type of molecule into a variety of fibrous structures with wide-ranging functional attributes remains challenging. Here, we harness the low-complexity (LC) sequence domain of fused in sarcoma (FUS) protein, an essential cellular nuclear protein with slow kinetics of amyloid fiber assembly, to construct random copolymer-like, multiblock, and self-sorted supramolecular fibrous networks with distinct structural features and fluorescent functionalities. We demonstrate the utilities of these networks in the templated, spatially controlled assembly of ligand-decorated gold nanoparticles, quantum dots, nanorods, DNA origami, and hybrid structures. Owing to the distinguishable nanoarchitectures of these nanofibers, this assembly is structure-dependent. By coupling a modular genetic strategy with kinetically controlled complex supramolecular self-assembly, we demonstrate that a single type of protein molecule can be used to engineer diverse one-dimensional supramolecular nanostructures with distinct functionalities.

Chemistry of supramolecular systems containing porphyrins and metal complexes

OpenAIRE

Araki, Koiti; Toma, Henrique Eisi

2002-01-01

Supramolecular chemistry is expected to keep a high developing pace in the next years, giving support to the advancement of molecular devices and nanotechnology. In this sense, porphyrins and their analogues should play a significant role as a consequence of their catalytic, electrocatalytic, photochemical and photoelectrochemical properties. In this review we focused on our own strategy based on coordination chemistry for the design and build-up of supermolecules and supramolecular structure...

Visualization of Stereoselective Supramolecular Polymers by Chirality-Controlled Energy Transfer.

Science.gov (United States)

Sarkar, Aritra; Dhiman, Shikha; Chalishazar, Aditya; George, Subi J

2017-10-23

Chirality-driven self-sorting is envisaged to efficiently control functional properties in supramolecular materials. However, the challenge arises because of a lack of analytical methods to directly monitor the enantioselectivity of the resulting supramolecular assemblies. Presented herein are two fluorescent core-substituted naphthalene-diimide-based donor and acceptor molecules with minimal structural mismatch and they comprise strong self-recognizing chiral motifs to determine the self-sorting process. As a consequence, stereoselective supramolecular polymerization with an unprecedented chirality control over energy transfer has been achieved. This chirality-controlled energy transfer has been further exploited as an efficient probe to visualize microscopically the chirality driven self-sorting. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reversible networks in supramolecular polymers

NARCIS (Netherlands)

Havermans - van Beek, D.J.M.

2007-01-01

Non–covalent interactions between low molecular weight polymers form the basis of supramolecular polymers. The material properties of such polymers are determined by the strength and lifetime of the non–covalent reversible interactions. Due to the reversibility of the interactions between the low

Self-Assembly of Supramolecular Aggregates Based on Sector- and Cone-Shaped Dendrons and Bolaamphiphiles

Science.gov (United States)

Shcherbina, M. A.; Chvalun, S. N.

2018-06-01

Using a number of classes of such sector-shaped macromolecules as derivatives of 2,3,4- and 3,4,5- tri(dodecyloxy)benzenesulfonic acid and dendrimers based on gallic acid as an example, the main stages in the formation of supramolecular ensembles are considered: the formation of individual supramolecular aggregates due to the weak noncovalent interactions of mesogenic groups, and the subsequent ordering within these aggregates, which lowers the free energy of a system. Supramolecular aggregates are in turn organized into two- or three-dimensional supramolecular lattices. It is shown that the shape of the supramolecular aggregates and its change along with temperature are functions of the chemical structure of the mesogenic group (resulting in the controlled design of complex self-organizing systems with a given response to external stimuli).

Electrostatically Driven Assembly of Charged Amphiphiles Forming Crystallized Membranes, Vesicles and Nanofiber Arrays

Science.gov (United States)

Leung, Cheuk Yui Curtis

Charged amphiphilic molecules can self-assemble into a large variety of objects including membranes, vesicles and fibers. These micro to nano-scale structures have been drawing increasing attention due to their broad applications, especially in biotechnology and biomedicine. In this dissertation, three self-assembled systems were investigated: +3/-1 self-assembled catanionic membranes, +2/-1 self-assembled catanionic membranes and +1 self-assembled nanofibers. Transmission electron microscopy (TEM) combined with synchrotron small and wide angle x-ray scattering (SAXS and WAXS) were used to characterize the coassembled structures from the mesoscopic to nanometer scale. We designed a system of +3 and -1 ionic amphiphiles that coassemble into crystalline ionic bilayer vesicles with large variety of geometries that resemble polyhedral cellular crystalline shells and archaea wall envelopes. The degree of ionization of the amphiphiles and their intermolecular electrostatic interactions can be controlled by varying pH. The molecular packing of these membranes showed a hexagonal to rectangular-C to hexagonal phase transition with increasing pH, resulting in significant changes to the membrane morphology. A similar mixture of +2 and -1 ionic amphiphiles was also investigated. In addition to varying pH, which controls the headgroup attractions, we also adjust the tail length of the amphiphiles to control the van der Waals interactions between the tails. A 2D phase diagram was developed to show how pH and tail length can be used to control the intermolecular packing within the membranes. Another system of self-assembled nanofiber network formed by positively charged amphiphiles was also studied. These highly charged fibers repel each other and are packed in hexagonal lattice with lattice constant at least eight times of the fiber diameter. The d-spacing and the crystal structure can be controlled by varying the solution concentration and temperature.

Spider-web amphiphiles as artificial lipid clusters: design, synthesis, and accommodation of lipid components at the air-water interface.

Science.gov (United States)

Ariga, Katsuhiko; Urakawa, Toshihiro; Michiue, Atsuo; Kikuchi, Jun-ichi

2004-08-03

As a novel category of two-dimensional lipid clusters, dendrimers having an amphiphilic structure in every unit were synthesized and labeled "spider-web amphiphiles". Amphiphilic units based on a Lys-Lys-Glu tripeptide with hydrophobic tails at the C-terminal and a polar head at the N-terminal are dendrically connected through stepwise peptide coupling. This structural design allowed us to separately introduce the polar head and hydrophobic tails. Accordingly, we demonstrated the synthesis of the spider-web amphiphile series in three combinations: acetyl head/C16 chain, acetyl head/C18 chain, and ammonium head/C16 chain. All the spider-web amphiphiles were synthesized in satisfactory yields, and characterized by 1H NMR, MALDI-TOFMS, GPC, and elemental analyses. Surface pressure (pi)-molecular area (A) isotherms showed the formation of expanded monolayers except for the C18-chain amphiphile at 10 degrees C, for which the molecular area in the condensed phase is consistent with the cross-sectional area assigned for all the alkyl chains. In all the spider-web amphiphiles, the molecular areas at a given pressure in the expanded phase increased in proportion to the number of units, indicating that alkyl chains freely fill the inner space of the dendritic core. The mixing of octadecanoic acid with the spider-web amphiphiles at the air-water interface induced condensation of the molecular area. From the molecular area analysis, the inclusion of the octadecanoic acid bears a stoichiometric characteristic; i.e., the number of captured octadecanoic acids in the spider-web amphiphile roughly agrees with the number of branching points in the spider-web amphiphile.

Monosaccharides as Versatile Units for Water-Soluble Supramolecular Polymers.

Science.gov (United States)

Leenders, Christianus M A; Jansen, Gijs; Frissen, Martijn M M; Lafleur, René P M; Voets, Ilja K; Palmans, Anja R A; Meijer, E W

2016-03-18

We introduce monosaccharides as versatile water-soluble units to compatibilise supramolecular polymers based on the benzene-1,3,5-tricarboxamide (BTA) moiety with water. A library of monosaccharide-based BTAs is evaluated, varying the length of the alkyl chain (hexyl, octyl, decyl and dodecyl) separating the BTA and saccharide units, as well as the saccharide units (α-glucose, β-glucose, α-mannose and α-galactose). In all cases, the monosaccharides impart excellent water compatibility. The length of the alkyl chain is the determining factor to obtain either long, one-dimensional supramolecular polymers (dodecyl spacer), small aggregates (decyl spacer) or molecularly dissolved (octyl and hexyl) BTAs in water. For the BTAs comprising a dodecyl spacer, our results suggest that a cooperative self-assembly process is operative and that the introduction of different monosaccharides does not significantly change the self- assembly behaviour. Finally, we investigate the potential of post-assembly functionalisation of the formed supramolecular polymers by taking advantage of dynamic covalent bond formation between the monosaccharides and benzoxaboroles. We observe that the supramolecular polymers readily react with a fluorescent benzoxaborole derivative permitting imaging of these dynamic complexes by confocal fluorescence microscopy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of Propeller-Shaped Supra-amphiphile for Construction of Enzyme-Responsive Fluorescent Vesicles.

Science.gov (United States)

Li, Jie; Liu, Kaerdun; Han, Yuchun; Tang, Ben Zhong; Huang, Jianbin; Yan, Yun

2016-10-04

Propeller-shaped molecules have been recognized to display fantastic AIE (aggregation induced emission), but they can hardly self-assemble into nanostructures. Herein, we for the first time report that ionic complexation between a water-soluble tetrapheneyl derivative and an enzyme substrate in aqueous media produces a propeller-shaped supra-amphiphile that self-assembles into enzyme responsive fluorescent vesicles. The supra-amphiphile was fabricated upon complexation between a water-soluble propeller-shaped AIE luminogen TPE-BPA and myristoylcholine chloride (MChCl) in aqueous media. MChCl filled in the intramolecular voids of propeller-shaped TPE-BPA upon supra-amphiphile formation, which endows the supra-amphiphile superior self-assembling ability to the component molecules thus leading to the formation of fluorescent vesicles. Because MChCl is the substrate of cholinesterases, the vesicles dissemble in the presence of cholinesterases, and the fluorescent intensity can be correlated to the level of enzymes. The resulting fluorescent vesicles may be used to recognize the site of Alzheimer's disease, to encapsulate the enzyme inhibitor, and to release the inhibitor at the disease site.

Amphiphilic block co-polymers: preparation and application in nanodrug and gene delivery.

Science.gov (United States)

Xiong, Xiao-Bing; Binkhathlan, Ziyad; Molavi, Ommoleila; Lavasanifar, Afsaneh

2012-07-01

Self-assembly of amphiphilic block co-polymers composed of poly(ethylene oxide) (PEO) as the hydrophilic block and poly(ether)s, poly(amino acid)s, poly(ester)s and polypropyleneoxide (PPO) as the hydrophobic block can lead to the formation of nanoscopic structures of different morphologies. These structures have been the subject of extensive research in the past decade as artificial mimics of lipoproteins and viral vectors for drug and gene delivery. The aim of this review is to provide an overview of the synthesis of commonly used amphiphilic block co-polymers. It will also briefly go over some pharmaceutical applications of amphiphilic block co-polymers as "nanodelivery systems" for small molecules and gene therapeutics. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Supramolecular gel electrophoresis of large DNA fragments.

Science.gov (United States)

Tazawa, Shohei; Kobayashi, Kazuhiro; Oyoshi, Takanori; Yamanaka, Masamichi

2017-10-01

Pulsed-field gel electrophoresis is a frequent technique used to separate exceptionally large DNA fragments. In a typical continuous field electrophoresis, it is challenging to separate DNA fragments larger than 20 kbp because they migrate at a comparable rate. To overcome this challenge, it is necessary to develop a novel matrix for the electrophoresis. Here, we describe the electrophoresis of large DNA fragments up to 166 kbp using a supramolecular gel matrix and a typical continuous field electrophoresis system. C 3 -symmetric tris-urea self-assembled into a supramolecular hydrogel in tris-boric acid-EDTA buffer, a typical buffer for DNA electrophoresis, and the supramolecular hydrogel was used as a matrix for electrophoresis to separate large DNA fragments. Three types of DNA marker, the λ-Hind III digest (2 to 23 kbp), Lambda DNA-Mono Cut Mix (10 to 49 kbp), and Marker 7 GT (10 to 165 kbp), were analyzed in this study. Large DNA fragments of greater than 100 kbp showed distinct mobility using a typical continuous field electrophoresis system. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diagram of state of stiff amphiphilic macromolecules

NARCIS (Netherlands)

Markov, Vladimir A.; Vasilevskaya, Valentina V.; Khalatur, Pavel G.; ten Brinke, Gerrit; Khokhlov, Alexei R.

2007-01-01

We studied coil-globule transitions in stiff-chain amphiphilic macromolecules via computer modeling and constructed phase diagrams for such molecules in terms of solvent quality and persistence length. We showed that the shape of the phase diagram essentially depends on the macromolecule degree of

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.

Facially amphiphilic thiol capped gold and silver nanoparticles

Indian Academy of Sciences (India)

Abstract. A series of bile acid-derived facially amphiphilic thiols have been used to cap sliver and gold nanoparticles. The self-assembling properties of these steroid-capped nanoparticles have been investigated and reported in this article.

Versatile antifouling polyethersulfone filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive.

Science.gov (United States)

Zhao, Yi-Fan; Zhang, Pei-Bin; Sun, Jian; Liu, Cui-Jing; Yi, Zhuan; Zhu, Li-Ping; Xu, You-Yi

2015-06-15

Here we describe the development of versatile antifouling polyethersulfone (PES) filtration membranes modified via surface grafting of zwitterionic polymers from a reactive amphiphilic copolymer additive. Amphiphilic polyethersulfone-block-poly(2-hydroxyethyl methacrylate) (PES-b-PHEMA) was beforehand designed and used as the blending additive of PES membranes prepared by phase inversion technique. The surface enriched PHEMA blocks on membrane surface acted as an anchor to immobilize the initiating site. Poly(sulfobetaine methacrylate) (PSBMA) were subsequently grafted onto the PES blend membranes by surface-initiated atom transfer radical polymerization (SI-ATRP). The analysis of surface chemistry confirmed the successful grafting of zwitterionic PSBMA brushes on PES membrane surface. The resulted PES-g-PSBMA membranes were capable of separating proteins from protein solution and oil from oil/water emulsion efficiently. Furthermore, the modified membranes showed high hydrophilicity and strongly antifouling properties due to the incorporation of well-defined PSBMA layer. In addition, the PES-g-PSBMA membranes exhibited excellent blood compatibility and durability during the washing process. The developed antifouling PES membranes are versatile and can find their applications in protein filtration, blood purification and oil/water separation, etc. Copyright © 2015 Elsevier Inc. All rights reserved.

Painting Supramolecular Polymers in Organic Solvents by Super-resolution Microscopy

Science.gov (United States)

2018-01-01

Despite the rapid development of complex functional supramolecular systems, visualization of these architectures under native conditions at high resolution has remained a challenging endeavor. Super-resolution microscopy was recently proposed as an effective tool to unveil one-dimensional nanoscale structures in aqueous media upon chemical functionalization with suitable fluorescent probes. Building upon our previous work, which enabled photoactivation localization microscopy in organic solvents, herein, we present the imaging of one-dimensional supramolecular polymers in their native environment by interface point accumulation for imaging in nanoscale topography (iPAINT). The noncovalent staining, typical of iPAINT, allows the investigation of supramolecular polymers’ structure in situ without any chemical modification. The quasi-permanent adsorption of the dye to the polymer is exploited to identify block-like arrangements within supramolecular fibers, which were obtained upon mixing homopolymers that were prestained with different colors. The staining of the blocks, maintained by the lack of exchange of the dyes, permits the imaging of complex structures for multiple days. This study showcases the potential of PAINT-like strategies such as iPAINT to visualize multicomponent dynamic systems in their native environment with an easy, synthesis-free approach and high spatial resolution. PMID:29697958

Molecular dynamics simulations of membrane deformation induced by amphiphilic helices of Epsin, Sar1p, and Arf1

Science.gov (United States)

Li, Zhen-Lu

2018-03-01

The N-terminal amphiphilic helices of proteins Epsin, Sar1p, and Arf1 play a critical role in initiating membrane deformation. The interactions of these amphiphilic helices with the lipid membranes are investigated in this study by combining the all-atom and coarse-grained simulations. In the all-atom simulations, the amphiphilic helices of Epsin and Sar1p are found to have a shallower insertion depth into the membrane than the amphiphilic helix of Arf1, but remarkably, the amphiphilic helices of Epsin and Sar1p induce higher asymmetry in the lipid packing between the two monolayers of the membrane. The insertion depth of amphiphilic helix into the membrane is determined not only by the overall hydrophobicity but also by the specific distributions of polar and non-polar residues along the helix. To directly compare their ability to deform the membrane, the coarse-grained simulations are performed to investigate the membrane deformation under the insertion of multiple helices. Project supported by the National Natural Science Foundation of China (Grant Nos. 91427302 and 11474155).

Dual responsive supramolecular hydrogel with electrochemical activity.

Science.gov (United States)

Du, Ping; Liu, Jianghua; Chen, Guosong; Jiang, Ming

2011-08-02

Supramolecular materials with reversible responsiveness to environmental changes are of particular research interest in recent years. Inclusion complexation between cyclodextrin (CD) and ferrocene (Fc) is well-known and extensively studied because of its reversible association-dissociation controlled by the redox state of Fc. Although there are quite a few reported nanoscale materials incorporating this host-guest pair, polymeric hydrogels with electrochemical activity based on this interactive pair are still rare. Taking advantage of our previous reported hybrid inclusion complex (HIC) hydrogel structure, a new Fc-HIC was designed and obtained with β-CD-modified quantum dots as the core and Fc-ended diblock co-polymer p(DMA-b-NIPAM) as the shell, to achieve an electrochemically active hydrogel at elevated temperatures. Considering the two independent cross-linking strategies in the network structure, i.e., the interchain aggregation of pNIPAM and inclusion complexation between CD and Fc on the surface of the quantum dots, the hydrogel was fully thermo-reversible and its gel-sol transition was achieved after the addition of either an oxidizing agent or a competitive guest to Fc.

pH-Sensitive Amphiphilic Block-Copolymers for Transport and Controlled Release of Oxygen

KAUST Repository

Patil, Yogesh Raghunath

2017-05-31

Saturated fluorocarbons, their derivatives and emulsions are capable of dissolving anomalously high amounts of oxygen and other gases. The mechanistic aspects of this remarkable effect remain to be explored experimentally. Here, the synthesis of a library of amphiphilic fluorous block-copolymers incorporating different fluorinated monomers is described, and the capacity of these copolymers for oxygen transport in water is systematically investigated. The structure of the fluorous monomer employed was found to have a profound effect on both the oxygen-carrying capacity and the gas release kinetics of the polymer emulsions. Furthermore, the release of O2 from the polymer dispersions could be triggered by changing the pH of the solution. This is the first example of a polymer-based system for controlled release of a non-polar, non-covalently entrapped respiratory gas.

pH-Sensitive Amphiphilic Block-Copolymers for Transport and Controlled Release of Oxygen

KAUST Repository

Patil, Yogesh Raghunath; Almahdali, Sarah; Vu, Khanh B.; Zapsas, Georgios; Hadjichristidis, Nikolaos; Rodionov, Valentin

2017-01-01

Saturated fluorocarbons, their derivatives and emulsions are capable of dissolving anomalously high amounts of oxygen and other gases. The mechanistic aspects of this remarkable effect remain to be explored experimentally. Here, the synthesis of a library of amphiphilic fluorous block-copolymers incorporating different fluorinated monomers is described, and the capacity of these copolymers for oxygen transport in water is systematically investigated. The structure of the fluorous monomer employed was found to have a profound effect on both the oxygen-carrying capacity and the gas release kinetics of the polymer emulsions. Furthermore, the release of O2 from the polymer dispersions could be triggered by changing the pH of the solution. This is the first example of a polymer-based system for controlled release of a non-polar, non-covalently entrapped respiratory gas.

Supramolecular interactions of oxidative stress biomarker glutathione with fluorone black

Science.gov (United States)

Hepel, Maria; Stobiecka, Magdalena

2018-03-01

Oxidative stress biomarkers, including glutathione (GSH) and related compounds, are involved in a variety of interactions enabling redox potential maintenance in living cells and protection against radicals. Since the oxidative stress is promoting and, in many cases, inducing serious illnesses, monitoring of GSH levels can aid in diagnostics and disease prevention. Herein, we report on the discovery of the formation of a supramolecular ensemble of GSH with fluorone black (9-phenyl fluorone, FB) which is optically active and enables sensitive determination of GSH by resonance elastic light scattering (RELS). We have found that supramolecular interactions of GSH with FB can be probed with spectroscopic, RELS, and electrochemical methods. Our investigations show that RELS intensity for FB solutions increases with GSH concentration while fluorescence emission of FB is not affected, as quenching begins only above 0.8 mM GSH. The UV-Vis difference spectra show a positive peak at 383 nm and a negative peak at 458 nm, indicating a higher-energy absorbing complex in comparison to the non-bonded FB host. Supramolecular interactions of FB with GSH have also been corroborated by electrochemical measurements involving two configurations of FB-GSH ensembles on electrodes: (i) an inverted orientation on Au-coated quartz crystal piezoelectrode (Au@SG-FB), with strong thiolate bonding to gold, and (ii) a non-inverted orientation on glassy carbon electrode (GCE@FB-GS), with weak π-π stacking attachment and efficient charge mediation through the ensemble. The formation of a supramolecular ensemble with hydrogen bonding has also been confirmed by quantum mechanical calculations. The discovery of supramolecular FB-GSH ensemble formation enables elucidating the mechanisms of strong RELS responses, changes in UV-Vis absorption spectra, and the electrochemical reactivity. Also, it provides new insights to the understanding of the efficient charge-transfer in redox potential homeostasis

Supramolecular interactions of oxidative stress biomarker glutathione with fluorone black.

Science.gov (United States)

Hepel, Maria; Stobiecka, Magdalena

2018-03-05

Oxidative stress biomarkers, including glutathione (GSH) and related compounds, are involved in a variety of interactions enabling redox potential maintenance in living cells and protection against radicals. Since the oxidative stress is promoting and, in many cases, inducing serious illnesses, monitoring of GSH levels can aid in diagnostics and disease prevention. Herein, we report on the discovery of the formation of a supramolecular ensemble of GSH with fluorone black (9-phenyl fluorone, FB) which is optically active and enables sensitive determination of GSH by resonance elastic light scattering (RELS). We have found that supramolecular interactions of GSH with FB can be probed with spectroscopic, RELS, and electrochemical methods. Our investigations show that RELS intensity for FB solutions increases with GSH concentration while fluorescence emission of FB is not affected, as quenching begins only above 0.8mM GSH. The UV-Vis difference spectra show a positive peak at 383nm and a negative peak at 458nm, indicating a higher-energy absorbing complex in comparison to the non-bonded FB host. Supramolecular interactions of FB with GSH have also been corroborated by electrochemical measurements involving two configurations of FB-GSH ensembles on electrodes: (i) an inverted orientation on Au-coated quartz crystal piezoelectrode (Au@SG-FB), with strong thiolate bonding to gold, and (ii) a non-inverted orientation on glassy carbon electrode (GCE@FB-GS), with weak π-π stacking attachment and efficient charge mediation through the ensemble. The formation of a supramolecular ensemble with hydrogen bonding has also been confirmed by quantum mechanical calculations. The discovery of supramolecular FB-GSH ensemble formation enables elucidating the mechanisms of strong RELS responses, changes in UV-Vis absorption spectra, and the electrochemical reactivity. Also, it provides new insights to the understanding of the efficient charge-transfer in redox potential homeostasis

Consequences of chirality on the dynamics of a water-soluble supramolecular polymer

NARCIS (Netherlands)

Baker, M.B.; Albertazzi, L.; Voets, Ilja K.; Leenders, C.M.A.; Palmans, A.R.A.; Pavan, G.M.; Meijer, E. W.

2015-01-01

The rational design of supramolecular polymers in water is imperative for their widespread use, but the design principles for these systems are not well understood. Herein, we employ a multi-scale (spatial and temporal) approach to differentiate two analogous water-soluble supramolecular polymers:

Supramolecular protein immobilization on lipid bilayers

NARCIS (Netherlands)

Bosmans, R.P.G.; Hendriksen, W.E.; Verheijden, Mark Lloyd; Eelkema, R.; Jonkheijm, Pascal; van Esch, J.H.; Brunsveld, Luc

2015-01-01

Protein immobilization on surfaces, and on lipid bilayers specifically, has great potential in biomolecular and biotechnological research. Of current special interest is the immobilization of proteins using supramolecular noncovalent interactions. This allows for a reversible immobilization and

Supramolecular Complexes Formed in Systems Bile Salt-Bilirubin-Silica

Science.gov (United States)

Vlasova, N. N.; Severinovskaya, O. V.; Golovkova, L. P.

The formation of supramolecular complexes between bilirubin and primary micelles of bile salts has been studied. The association constants of bile salts and binding of bilirubin with these associates have been determined. The adsorption of bilirubin and bile salts from individual and mixed aqueous solutions onto hydrophobic silica surfaces has been investigated. The interaction of bilirubin with primary bile salt micelles and the strong retention in mixed micelles, which are supramolecular complexes, result in the adsorption of bilirubin in free state only.

Isentropic expansion and related thermodynamic properties of non-ionic amphiphile-water mixtures.

Science.gov (United States)

Reis, João Carlos R; Douhéret, Gérard; Davis, Michael I; Fjellanger, Inger Johanne; Høiland, Harald

2008-01-28

A concise thermodynamic formalism is developed for the molar isentropic thermal expansion, ES,m = ( partial differential Vm/ partial differential T)(Sm,x), and the ideal and excess quantities for the molar, apparent molar and partial molar isentropic expansions of binary liquid mixtures. Ultrasound speeds were determined by means of the pulse-echo-overlap method in aqueous mixtures of 2-methylpropan-2-ol at 298.15 K over the entire composition range. These data complement selected extensive literature data on density, isobaric heat capacity and ultrasound speed for 9 amphiphile (methanol, ethanol, propan-1-ol, propan-2-ol, 2-methylpropan-2-ol, ethane-1,2-diol, 2-methoxyethanol, 2-ethoxyethanol or 2-butoxyethanol)-water binary systems, which form the basis of tables listing molar and excess molar isobaric expansions and heat capacities, and molar and excess molar isentropic compressions and expansions at 298.15 K and at 65 fixed mole fractions spanning the entire composition range and fine-grained in the water-rich region. The dependence on composition of these 9 systems is graphically depicted for the excess molar isobaric and isentropic expansions and for the excess partial molar isobaric and isentropic expansions of the amphiphile. The analysis shows that isentropic thermal expansion properties give a much stronger response to amphiphile-water molecular interactions than do their isobaric counterparts. Depending on the pair property-system, the maximum excess molar isentropic value is generally twenty- to a hundred-fold greater than the corresponding maximum isobaric value, and occurs at a lower mole fraction of the amphiphile. Values at infinite dilution of the 9 amphiphiles in water are given for the excess partial molar isobaric heat capacity, isentropic compression, isobaric expansion and isentropic expansion. These values are interpreted in terms of the changes occurring when amphiphile molecules cluster into an oligomeric form. Present results are discussed

Nanoparticles functionalized with supramolecular host-guest systems for nanomedicine and healthcare.

Science.gov (United States)

Wu, Zilong; Song, Nan; Menz, Ryan; Pingali, Bharadwaj; Yang, Ying-Wei; Zheng, Yuebing

2015-05-01

Synthetic macrocyclic host compounds can interact with suitable guest molecules via noncovalent interactions to form functional supramolecular systems. With the synergistic integration of the response of molecules and the unique properties at the nanoscale, nanoparticles functionalized with the host-guest supramolecular systems have shown great potentials for a broad range of applications in the fields of nanoscience and nanotechnology. In this review article, we focus on the applications of the nanoparticles functionalized with supramolecular host-guest systems in nanomedicine and healthcare, including therapeutic delivery, imaging, sensing and removal of harmful substances. A large number of examples are included to elucidate the working mechanisms, advantages, limitations and future developments of the nanoparticle-supramolecule systems in these applications.

Morphological changes of monolayers of two polymerizable pyridine amphiphiles upon complexation with Cu(II) ions at the air-water interface

NARCIS (Netherlands)

Werkman, P.J.; Schouten, A.J.; Noordegraaf, M.A.; Kimkes, P.; Sudhölter, E.J.R.

1998-01-01

The monolayer behavior of two amphiphilic, diacetylenic units containing pyridine Ligands at the air-water interface is studied by measuring the surface pressure-area isotherms and by Brewster angle microscopy(BAM). Both amphiphiles form stable monolayers at the air-water interface. The amphiphile

Effect of ionizing radiation exposure in the morphology of modified HDPE with amphiphilic particles

International Nuclear Information System (INIS)

Saldanha, Ana Luiza M.; Vivas, Viviane; Zylberberg, Marcel P.; Silva, Tamara I.; Cardoso, Andre Luis V.; Pereira, Iaci M.; Patricio, Patricia S.O.

2015-01-01

One of the techniques used to improve the properties of high performance polymers is the addition of hybrid particles in the polymer. In this context, amphiphilic particles were synthesized in order to provide surface characteristics that enhance the interaction of the interface with the polymeric matrix of high density polyethylene (HDPE). The amphiphilic particles were added to matrix of HDPE and the modified polymer composites were exposed to ionizing radiation (x-rays) for different times. The changes caused by exposure to ionizing radiation in the composite morphology was observed through the small angle x-ray technique. The results suggest that the addition of amphiphilic particles increased the stability of the composite to degradation by radiation. (author)

Supramolecular chemistry and crystal engineering

Indian Academy of Sciences (India)

supramolecular architectures, network structures, multi-component host–guest systems, cocrys- tals, and ... structures is illustrated by two important prototypes – the large unit cell of elusive saccharin hydrate ..... N––– H ··· π interaction is not seen in this view. (d) Infinite .... to atmospheric water vapor without color loss or.

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career.

Science.gov (United States)

Anslyn, Eric V

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 me to the fields of supramolecular chemistry and molecular orbital theory, because I grew up in a household filled with art. In addition to art, my childhood was filled with repairing and constructing mechanical entities, such as internal combustion motors, where many components work together to achieve a function. Analogously, the field of supramolecular chemistry creates systems of high complexity that achieve functions or perform tasks. Therefore, in retrospect a career in supramolecular chemistry appears to be simply an extension of childhood hobbies involving art and auto-mechanics.

Self-Assembly of Amphiphilic Block Copolypeptoids with C 2 -C 5 Side Chains in Aqueous Solution

KAUST Repository

Fetsch, Corinna; Flecks, Silvana; Gieseler, Dan; Marschelke, Claudia; Ulbricht, Juliane; van Pé e, Karl-Heinz; Luxenhofer, Robert

2014-01-01

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Nowadays, amphiphilic molecules play an important role in our life. In medical applications, amphiphilic block copolymers have attracted much attention as excipients in drug delivery systems. Here

Supramolecular chemistry - interdisciplinary branch of science

International Nuclear Information System (INIS)

Radecka-Paryzek, W.

1997-01-01

The scientific problems connected with supramolecular chemistry have been reviewed. The basic concepts have been defined as well as rules governed of macromolecules formation. The special emphasize has been put on present and possible in future application of such systems

A Supramolecular Approach to Medicinal Chemistry: Medicine Beyond the Molecule

Science.gov (United States)

Smith, David K.

2005-03-01

This article focuses on the essential roles played by intermolecular forces in mediating the interactions between chemical molecules and biological systems. Intermolecular forces constitute a key topic in chemistry programs, yet can sometimes seem disconnected from real-life applications. However, by taking a "supramolecular" view of medicinal chemistry and focusing on interactions between molecules, it is possible to come to a deeper understanding of recent developments in medicine. This allows us to gain a real insight into the interface between biology and chemistry—an interdisciplinary area that is crucial for the development of modern medicinal products. This article emphasizes a conceptual view of medicinal chemistry, which has important implications for the future, as the supramolecular approach to medicinal-chemistry products outlined here is rapidly allowing nanotechnology to converge with medicine. In particular, this article discusses recent developments including the rational design of drugs such as Relenza and Tamiflu, the mode of action of vancomycin, and the mechanism by which bacteria develop resistance, drug delivery using cyclodextrins, and the importance of supramolecular chemistry in understanding protein aggregation diseases such as Alzheimer's and Creutzfield Jacob. The article also indicates how taking a supramolecular approach will enable the development of new nanoscale medicines.

Micro- and nanophase separations in hierarchical self-assembly of strongly amphiphilic block copolymer-based ionic supramolecules

DEFF Research Database (Denmark)

Ayoubi, Mehran Asad; Zhu, Kaizheng; Nyström, Bo

2013-01-01

block), a class of ionic supramolecules are successfully synthesized whose molecular architecture consists of a poly(styrene) PS block (Linear block) covalently connected to a strongly amphiphilic comb-like block (AmphComb block), i.e. Linear-b-AmphComb. In the melt state, these ionic supramolecules can.......20 (SLL/C and SBCC/C) and ∼0.28 (C/L). Finally, the specific influences of the strongly amphiphilic nature of the AmphComb blocks on the observed morphological and hierarchical behaviours of our system are discussed. For reference, stoichiometric strongly amphiphilic comb-like (AmphComb) ionic...

Facially amphiphilic thiol capped gold and silver nanoparticles

Indian Academy of Sciences (India)

Wintec

*For correspondence. Also at the Chemical Biology Unit,. Jawaharlal Nehru Centre for Advanced Scientific Research,. Bangalore 560 064. Facially amphiphilic thiol capped gold and silver nanoparticles. †. SHREEDHAR BHAT a and UDAY MAITRA*. Department of Organic Chemistry, Indian Institute of Science, Bangalore ...

Nucleic acid amphiphiles : synthesis and self-assembled nanostructures

NARCIS (Netherlands)

Kwak, Minseok; Herrmann, Andreas; Clever, Guido; Mao, Chengde; Shionoya, Mitsuhiko; Stulz, Eugen

2011-01-01

This review provides an overview of a relatively new class of bio-conjugates, DNA amphiphiles, which consist of oligonucleotides covalently bonded to synthetic hydrophobic units. The reader will find the basic principles for the structural design and preparation methods of the materials. Moreover,

Ammonium amphiphiles carrying mesogenic units : synthesis, properties, applications

NARCIS (Netherlands)

Everaars, M.D.

1997-01-01

When the structural characteristics of amphiphiles and thermotropic liquid crystals are combined in one molecule i.e. a polar headgroup with apolar tails and mesogenic units, compounds are obtained which can exhibit both thermotropic and lyotropic mesomorphism. This class of compounds is

Self-Assembly of Coordinative Supramolecular Polygons with Open Binding Sites.

Science.gov (United States)

Zheng, Yao-Rong; Wang, Ming; Kobayashi, Shiho; Stang, Peter J

2011-04-27

The design and synthesis of coordinative supramolecular polygons with open binding sites is described. Coordination-driven self-assembly of 2,6-bis(pyridin-4-ylethynyl)pyridine with 60° and 120° organoplatinum acceptors results in quantitative formation of a supramolecular rhomboid and hexagon, respectively, both bearing open pyridyl binding sites. The structures were determined by multinuclear ((31)P and (1)H) NMR spectroscopy and electrospray ionization (ESI) mass spectrometry, along with a computational study.

Intelligent Chiral Sensing Based on Supramolecular and Interfacial Concepts

Directory of Open Access Journals (Sweden)

Hironori Izawa

2010-07-01

Full Text Available Of the known intelligently-operating systems, the majority can undoubtedly be classed as being of biological origin. One of the notable differences between biological and artificial systems is the important fact that biological materials consist mostly of chiral molecules. While most biochemical processes routinely discriminate chiral molecules, differentiation between chiral molecules in artificial systems is currently one of the challenging subjects in the field of molecular recognition. Therefore, one of the important challenges for intelligent man-made sensors is to prepare a sensing system that can discriminate chiral molecules. Because intermolecular interactions and detection at surfaces are respectively parts of supramolecular chemistry and interfacial science, chiral sensing based on supramolecular and interfacial concepts is a significant topic. In this review, we briefly summarize recent advances in these fields, including supramolecular hosts for color detection on chiral sensing, indicator-displacement assays, kinetic resolution in supramolecular reactions with analyses by mass spectrometry, use of chiral shape-defined polymers, such as dynamic helical polymers, molecular imprinting, thin films on surfaces of devices such as QCM, functional electrodes, FET, and SPR, the combined technique of magnetic resonance imaging and immunoassay, and chiral detection using scanning tunneling microscopy and cantilever technology. In addition, we will discuss novel concepts in recent research including the use of achiral reagents for chiral sensing with NMR, and mechanical control of chiral sensing. The importance of integration of chiral sensing systems with rapidly developing nanotechnology and nanomaterials is also emphasized.

Supramolecular fluorene based materials

OpenAIRE

Abbel, R.J.

2008-01-01

This thesis describes the use of noncovalent interactions in order to manipulate and control the self-assembly and morphology of electroactive fluorene-based materials. The supramolecular arrangement of p-conjugated polymers and oligomers can strongly influence their electronic and photophysical properties. Therefore, a detailed understanding of such organisation processes is essential for the optimisation of the performance of these materials as applied in optoelectronic devices. In order to...

Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

International Nuclear Information System (INIS)

Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo

2016-01-01

Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification

Solid structures of the stepwise self-assembled copillar[5]arene-based supramolecular polymers

Energy Technology Data Exchange (ETDEWEB)

Park, Yeon Sil; Hwang, Seong Min; Shin, Jae Yeon; Paek, Kyung Soo [Dept. of Chemistry, Soongsil University, Seoul (Korea, Republic of)

2016-10-15

Development of supramolecular polymer has attracted much interest because of their interesting properties such as stimuli-responsiveness, recycling, self-healing and degradability, and their consequential applications. The essential feature of this class of polymers is the self-assembly of discrete monomeric subunits via non-covalent interactions or dynamic covalent bonds. Among the many monomeric subunits, pillar[n]arenes have been ideal building blocks for the fabrication of polymeric supramolecules because of their intrinsic characteristics. The ring-shaped morphologies in supramolecular polymer P are probably due to the tendency of the end-to-end connection in the solid state of long flexible supramolecular chains. The size increase of nano-rings as the stepwise addition increases might be due to the fact that the linear supramolecular polymer P in solution seems to be maintained until the nano-ring formation by solidification.

Side-Chain Supramolecular Polymers Employing Conformer Independent Triple Hydrogen Bonding Arrays

OpenAIRE

Gooch, Adam; Murphy, Natasha S.; Thomson, Neil H.; Wilson, Andrew J.

2013-01-01

Derivatives of thymine have been extensively used to promote supramolecular materials assembly. Such derivatives can be synthetically challenging to access and may be susceptible to degradation. The current article uses a conformer-independent acceptor-donor-acceptor array (ureidopyrimidine) which forms moderate affinity interactions with diamidopyridine derivatives to effect supramolecular blend formation between polystyrene and poly(methyl methacrylate) polymers obtained by RAFT which have ...

Supramolecular photocatalyst of RGO-cyclodextrin-TiO2

International Nuclear Information System (INIS)

Shen, Jianfeng; Li, Na; Ye, Mingxin

2013-01-01

Graphical abstract: Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved, which showed high photocatalytic activity and adsorption capacity. Highlights: •Supramolecular photocatalyst of RGO-cyclodextrin-TiO 2 was achieved. •β-CD molecules acted as linkers between RGO and monodisperse TiO 2 nanoparticles. •Reduction of GO and preparation of RGO-cyclodextrin-TiO 2 was simultaneous. •The prepared RGO-cyclodextrin-TiO 2 shows high photocatalytic activity and adsorption capacity. -- Abstract: Reduced graphene oxide (RGO)/β-cyclodextrin (β-CD)/titanium oxide (TiO 2 ) supramolecular photocatalyst was synthesized with a one-pot hydrothermal method. The reducing process was accomplished with the attaching of β-CD and generation of TiO 2 . β-CD acted as a linker between RGO and monodisperse TiO 2 nanoparticles. The structure and composition of the hybrid had been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, thermal gravimetric analysis, X-ray diffraction and Transmission electron microscopy. The as-prepared RGO-CD-TiO 2 showed significant enhanced performance for phenol and Cr (VI) removal, due to the effective transfer of photo-generated electron from TiO2 to RGO and improved absorbance performance of the hybrid

The search for new amphiphiles: synthesis of a modular, high-throughput library

Directory of Open Access Journals (Sweden)

George C. Feast

2014-07-01

Full Text Available Amphiphilic compounds are used in a variety of applications due to their lyotropic liquid-crystalline phase formation, however only a limited number of compounds, in a potentially limitless field, are currently in use. A library of organic amphiphilic compounds was synthesised consisting of glucose, galactose, lactose, xylose and mannose head groups and double and triple-chain hydrophobic tails. A modular, high-throughput approach was developed, whereby head and tail components were conjugated using the copper-catalysed azide–alkyne cycloaddition (CuAAC reaction. The tails were synthesised from two core alkyne-tethered intermediates, which were subsequently functionalised with hydrocarbon chains varying in length and degree of unsaturation and branching, while the five sugar head groups were selected with ranging substitution patterns and anomeric linkages. A library of 80 amphiphiles was subsequently produced, using a 24-vial array, with the majority formed in very good to excellent yields. A preliminary assessment of the liquid-crystalline phase behaviour is also presented.

Liquid-solid extraction of metallic cations by cationic amphiphiles

International Nuclear Information System (INIS)

Mueller, Wolfram; Sievers, Torsten K.; Zemb, Thomas; Diat, Olivier; Sievers, Torsten K.; Dejugnat, Christophe

2012-01-01

In the field of selective metal ion separation, liquid-liquid extraction is usually conducted through an emulsion mixing of hydrophobic complexants dispersed in an organic phase and acidic water containing the ionic species. Recently, it has been shown that amphiphilic complexants could influence strongly extraction efficiency by enhancing the interfacial interaction between the metal ion in the aqueous and the complexant in the organic phase. Moreover, these amphiphiles can also substitute the organic phase if an appropriate aliphatic chain is chosen. The dispersion of such amphiphilic complexants in an aqueous solution of salt mixtures is not only attractive for studying specific interactions but also to better the understanding of complex formation in aqueous solution of multivalent metal ions, such as lanthanides and actinides. This understanding is of potential interest for a broad range of industries including purification of rare earth metals and pollute treatment e.g. of fission byproducts. This principle can also be applied to liquid-solid extraction, where the final state of the separation is a solid phase containing the selectively extracted ions. Indeed, a novel solid-liquid extraction method exploits the selective precipitation of metal ions from an aqueous salt mixture using a cationic surfactant, below its Krafft point (temperature below which the long aliphatic chains of surfactant crystallize). This technique has been proven to be highly efficient for the separation of actinides and heavy metal using long chain ammonium or pyridinium amphiphiles. The most important point in this process is the recognition of cationic metal ions by cationic surfactants. By computing the free energy of the polar head group per micelle as a function of the different counter-anions, we have demonstrated for the first time that different interactions exist between the micellar surface and the ions. These interactions depend on the nature of the cation but also on

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.

Maltose-neopentyl glycol (MNG) amphiphiles for solubilization, stabilization and crystallization of membrane proteins.

Science.gov (United States)

Chae, Pil Seok; Rasmussen, Søren G F; Rana, Rohini R; Gotfryd, Kamil; Chandra, Richa; Goren, Michael A; Kruse, Andrew C; Nurva, Shailika; Loland, Claus J; Pierre, Yves; Drew, David; Popot, Jean-Luc; Picot, Daniel; Fox, Brian G; Guan, Lan; Gether, Ulrik; Byrne, Bernadette; Kobilka, Brian; Gellman, Samuel H

2010-12-01

The understanding of integral membrane protein (IMP) structure and function is hampered by the difficulty of handling these proteins. Aqueous solubilization, necessary for many types of biophysical analysis, generally requires a detergent to shield the large lipophilic surfaces of native IMPs. Many proteins remain difficult to study owing to a lack of suitable detergents. We introduce a class of amphiphiles, each built around a central quaternary carbon atom derived from neopentyl glycol, with hydrophilic groups derived from maltose. Representatives of this maltose-neopentyl glycol (MNG) amphiphile family show favorable behavior relative to conventional detergents, as manifested in multiple membrane protein systems, leading to enhanced structural stability and successful crystallization. MNG amphiphiles are promising tools for membrane protein science because of the ease with which they may be prepared and the facility with which their structures may be varied.

Uses of neutron scattering in supramolecular chemistry

International Nuclear Information System (INIS)

Lindoy, L.F.

1998-01-01

Full text: A major thrust in recent chemical research has been the development of supramolecular chemistry 1 - broadly the chemistry of large multicomponent molecular assemblies in which the component structural units are held together by either covalent linkages or by a variety of weaker (non-covalent) interactions that include hydrogen bonding, dipole stacking, π-stacking, van der Waals q forces and favourable hydrophobic interactions. Much of the activity in the area has been motivated by the known behaviour of biological molecules (such as enzymes). Thus molecular assemblies are ubiquitous in natural systems but, with a limited number of exceptions, have only recently been the subject of increasing investigation by chemists. A feature of much of this recent work has been its focus on molecular design for achieving complementarity between single molecule hosts and guests. The use of single crystal neutron diffraction coupled with molecular modelling and a range of other techniques to investigate the nature of individual supramolecular systems will be discussed. By way of example, in one such study the supramolecular array formed by co-crystallisation of 1,2- diaminoethane and benzoic acid has been investigated; the system self-assembles into an unusual layered structure composed of two-dimensional hydrogen bonded networks sandwiched between layers of edge-to-face stacked aromatic systems. The number of hydrogen-bond donors and acceptors is balanced in this structure

SYNTHESIS OF AMPHIPHILIC COMB-SHAPED COPOLYMERS USED FOR SURFACE MODIFICATION OF PVDF MEMBRANES

Institute of Scientific and Technical Information of China (English)

徐又一

2009-01-01

The synthesis of a novel amphiphilic comb-shaped copolymer consisting of a main chain of styrene-(N-(4- hydroxyphenyl) maleimide)(SHMI) copolymer and poly(ethylene glycol) methyl ether methacrylate(PEGMA) side groups was achieved by atom transfer radical polymerization(ATRP).The amphiphilic copolymers were characterized by ~1H-NMR, Fourier transform infrared(FTIR) spectroscopy and gel permeation chromatography(GPC).From thermogravimetric analysis (TGA),the decomposition temperature of SHMI-g-PEGMA is low...

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.

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

Adsorption of different amphiphilic molecules onto polystyrene latices.

Science.gov (United States)

Jódar-Reyes, A B; Ortega-Vinuesa, J L; Martín-Rodríguez, A

2005-02-15

In order to know the influence of the surface characteristics and the chain properties on the adsorption of amphiphilic molecules onto polystyrene latex, a set of experiments to study the adsorption of ionic surfactants, nonionic surfactants and an amphiphilic synthetic peptide on different latex dispersions was performed. The adsorbed amount versus the equilibrium surfactant concentration was determined. The main adsorption mechanism was the hydrophobic attraction between the nonpolar tail of the molecule and the hydrophobic regions of the latex surface. This attraction overcame the electrostatic repulsion between chains and latex surface with identical charge sign. However, the electrostatic interactions chain-surface and chain-chain also played a role. General patterns for the adsorption of ionic chains on charged latex surfaces could be established. Regarding the shape, the isotherms presented different plateaus corresponding to electrostatic effects and conformational changes. The surfactant size also affects the adsorption results: the higher the hydrophilic moiety in the surfactant molecule the lower the adsorbed amount.

A supramolecular strategy for self-mobile adsorption sites in affinity membrane.

Science.gov (United States)

Lin, Ligang; Dong, Meimei; Liu, Chunyu; Wei, Chenjie; Wang, Yuanyuan; Sun, Hui; Ye, Hui

2014-09-01

Disclosed here is the design of a novel supramolecular membrane with self-mobile adsorption sites for biomolecules purification. In the 3D micropore channels of membrane matrix, the ligands are conjugated onto the cyclic compounds in polyrotaxanes for protein adsorption. During membrane filtration, the adsorption sites can rotate and/or slide along the axial chain, which results in the enhanced adsorption capacity. The excellent performance of supra-molecular membrane is related with the dynamic working manner of adsorption sites, which plays a crucial role on avoiding spatial mismatching and short-circuit effect. The supra-molecular strategy described here has general suggestions for the "sites" involved technologies such as catalysis, adsorption, and sensors, which is of broad interest. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Art, auto-mechanics, and supramolecular chemistry. A merging of hobbies and career

Directory of Open Access Journals (Sweden)

Eric V. Anslyn

2016-02-01

Full Text Available 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 me to the fields of supramolecular chemistry and molecular orbital theory, because I grew up in a household filled with art. In addition to art, my childhood was filled with repairing and constructing mechanical entities, such as internal combustion motors, where many components work together to achieve a function. Analogously, the field of supramolecular chemistry creates systems of high complexity that achieve functions or perform tasks. Therefore, in retrospect a career in supramolecular chemistry appears to be simply an extension of childhood hobbies involving art and auto-mechanics.

Formation and Mechanism of Superhydrophobic/Hydrophobic Surfaces Made from Amphiphiles through Droplet-Mediated Evaporation-Induced Self-Assembly.

Science.gov (United States)

Dong, Fangyuan; Zhang, Mi; Tang, Wai-Wa; Wang, Yi

2015-04-23

Superhydrophobic/hydrophobic surfaces have attracted wide attention because of their broad applications in various regions, including coating, textile, packaging, electronic devices, and bioengineering. Many studies have been focused on the fabrication of superhydrophobic/hydrophobic surfaces using natural materials. In this paper, superhydrophobic/hydrophobic surfaces were formed by an amphiphilic natural protein, zein, using electrospinning. Water contact angle (WCA) and scanning electron microscopy (SEM) were used to characterize the hydrophobicity and surface morphology of the electrospun structures. The highest WCA of the zein electrospun surfaces could reach 155.5 ± 1.4°. To further understand the mechanism of superhydrophobic surface formation from amphiphiles using electrospinning, a synthetic amphiphilic polymer was selected, and also, a method similar to electrospinning, spray drying, was tried. The electrospun amphiphilic polymer surface showed a high hydrophobicity with a WCA of 141.4 ± 0.7°. WCA of the spray-dried zein surface could reach 125.3 ± 2.1°. The secondary structures of the zein in the electrospun film and cast-dried film were studied using ATR-FTIR, showing that α-helix to β-sheet transformation happened during the solvent evaporation in the cast drying process but not in the electrospinning process. A formation mechanism was proposed on the basis of the orientation of the amphiphiles during the solvent evaporation of different fabrication methods. The droplet-based or jet-based evaporation during electrospinning and spray drying led to the formation of the superhydrophobic/hydrophobic surface by the accumulation of the hydrophobic groups of the amphiphiles on the surface, while the surface-based evaporation during cast drying led to the formation of the hydrophilic surface by the accumulation of the hydrophilic groups of the amphiphiles on the surface.

Effects of Lateral and Terminal Chains of X-Shaped Bolapolyphiles with Oligo(phenylene ethynylene Cores on Self-Assembly Behavior. Part 2: Domain Formation by Self-Assembly in Lipid Bilayer Membranes

Directory of Open Access Journals (Sweden)

Stefan Werner

2017-09-01

Full Text Available Supramolecular self-assembly of membrane constituents within a phospholipid bilayer creates complex functional platforms in biological cells that operate in intracellular signaling, trafficking and membrane remodeling. Synthetic polyphilic compounds of macromolecular or small size can be incorporated into artificial phospholipid bilayers. Featuring three or four moieties of different philicities, they reach beyond ordinary amphiphilicity and open up avenues to new functions and interaction concepts. Here, we have incorporated a series of X-shaped bolapolyphiles into DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine bilayers of giant unilamellar vesicles. The bolapolyphiles consist of a rod-like oligo(phenylene ethynylene (OPE core, hydrophilic glycerol-based headgroups with or without oligo(ethylene oxide expansions at both ends and two lateral alkyl chains attached near the center of the OPE core. In the absence of DPPC and water, the compounds showed thermotropic liquid-crystalline behavior with a transition between polyphilic and amphiphilic assembly (see part 1 in this issue. In DPPC membranes, various trends in the domain morphologies were observed upon structure variations, which entailed branched alkyl chains of various sizes, alkyl chain semiperfluorination and size expansion of the headgroups. Observed effects on domain morphology are interpreted in the context of the bulk behavior (part 1 and of a model that was previously developed based on spectroscopic and physicochemical data.

Dehydration-induced redistribution of amphiphilic molecules between cytoplasm and lipids is associated with desiccation tolerance in seeds

NARCIS (Netherlands)

Buitink, J.; Leprince, O.; Hoekstra, F.A.

2000-01-01

This study establishes a relationship between desiccation tolerance and the transfer of amphiphilic molecules from the cytoplasm into lipids during drying, using electron paramagnetic resonance spectroscopy of amphiphilic spin probes introduced into imbibed radicles of pea (Pisum sativum) and

Surface-Assisted Self-Assembly Strategies Leading to Supramolecular Hydrogels.

Science.gov (United States)

Vigier-Carrière, Cécile; Boulmedais, Fouzia; Schaaf, Pierre; Jierry, Loïc

2018-02-05

Localized molecular self-assembly processes leading to the growth of nanostructures exclusively from the surface of a material is one of the great challenges in surface chemistry. In the last decade, several works have been reported on the ability of modified or unmodified surfaces to manage the self-assembly of low-molecular-weight hydrogelators (LMWH) resulting in localized supramolecular hydrogel coatings mainly based on nanofiber architectures. This Minireview highlights all strategies that have emerged recently to initiate and localize LMWH supramolecular hydrogel formation, their related fundamental issues and applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Facile preparation of luminescent and intelligent gold nanodots based on supramolecular self-assembly

International Nuclear Information System (INIS)

Shi Yunfeng; Li Sujuan; Zhou Yahui; Zhai Qingpan; Hu Mengyue; Cai Fensha; Du Jimin; Liang Jiamiao; Zhu Xinyuan

2012-01-01

A new strategy for preparing luminescent and intelligent gold nanodots based on supramolecular self-assembly is described in this paper. The supramolecular self-assembly was initiated through electrostatic interactions and ion pairing between palmitic acid and hyperbranched poly(ethylenimine). The resulting structures not only have the dynamic reversible properties of supramolecules but also possess torispherical and highly branched architectures. Thus they can be regarded as a new kind of ideal nanoreactor for preparing intelligent Au nanodots. By preparing Au nanodots within this kind of supramolecular self-assembly, the environmental sensitivity of intelligent polymers and the optical, electrical properties of Au nanodots can be combined, endowing the Au nanodots with intelligence. In this paper, a supramolecular self-assembly process based on dendritic poly(ethylenimine) and palmitic acid was designed and then applied to prepare fluorescent and size-controlled Au nanodots. The pH response of Au nanodots embodied by phase transfer from oil phase to water phase was also investigated. (paper)

Self-assembling supramolecular systems of different symmetry formed by wedged macromolecular dendrons

Energy Technology Data Exchange (ETDEWEB)

Shcherbina, M. A., E-mail: shcherbina@ispm.ru; Bakirov, A. V. [Russian Academy of Sciences, Institute of Synthetic Polymer Materials (Russian Federation); Yakunin, A. N. [Karpov Institute of Physical Chemistry (Russian Federation); Percec, V. [University of Pennsylvania (United States); Beginn, U. [Universitaet Osnabrueck, Institut fuer Chemie (Germany); Moeller, M. [Institute for Technical and Macromolecular Chemistry (Germany); Chvalun, S. N. [Russian Academy of Sciences, Institute of Synthetic Polymer Materials (Russian Federation)

2012-03-15

The main stages of the self-assembling of supramolecular ensembles have been revealed by studying different functional wedged macromolecules: polymethacrylates with tapered side chains based on gallic acid, their macromonomers, and salts of 2,3,4- and 3,4,5-tris(dodecyloxy)benzenesulphonic acid. The first stage is the formation of individual supramolecular aggregates (long cylinders or spherical micelles) due to the weak noncovalent interactions of mesogenic groups and the subsequent ordering in these aggregates, which is accompanied by a decrease in the free energy of the system. Supramolecular aggregates, in turn, form 2D or 3D lattices. The shape of supramolecular aggregates and its change with temperature are delicate functions of the mesogen chemical structure; this circumstance makes it possible to rationally design complex self-assembling systems with the ability to respond smartly to external stimuli. X-ray diffraction analysis allows one to study the structure of supramolecular systems with different degrees of order, determine the type of mesophases formed by these systems, and reveal the phase behavior of the material. Particular attention has been paid to the method for reconstruction of electron density distribution from the relative reflection intensity. The application of a suite of experimental methods, including wide- and small-angle X-ray diffraction, molecular modeling, differential scanning calorimetry, and polarization optical microscopy, allows one to establish the relationship between the shape of the structural unit (molecule or molecular aggregate), the nature of the interaction, and the phase behavior of the material.

Self-assembling supramolecular systems of different symmetry formed by wedged macromolecular dendrons

International Nuclear Information System (INIS)

Shcherbina, M. A.; Bakirov, A. V.; Yakunin, A. N.; Percec, V.; Beginn, U.; Möller, M.; Chvalun, S. N.

2012-01-01

The main stages of the self-assembling of supramolecular ensembles have been revealed by studying different functional wedged macromolecules: polymethacrylates with tapered side chains based on gallic acid, their macromonomers, and salts of 2,3,4- and 3,4,5-tris(dodecyloxy)benzenesulphonic acid. The first stage is the formation of individual supramolecular aggregates (long cylinders or spherical micelles) due to the weak noncovalent interactions of mesogenic groups and the subsequent ordering in these aggregates, which is accompanied by a decrease in the free energy of the system. Supramolecular aggregates, in turn, form 2D or 3D lattices. The shape of supramolecular aggregates and its change with temperature are delicate functions of the mesogen chemical structure; this circumstance makes it possible to rationally design complex self-assembling systems with the ability to respond smartly to external stimuli. X-ray diffraction analysis allows one to study the structure of supramolecular systems with different degrees of order, determine the type of mesophases formed by these systems, and reveal the phase behavior of the material. Particular attention has been paid to the method for reconstruction of electron density distribution from the relative reflection intensity. The application of a suite of experimental methods, including wide- and small-angle X-ray diffraction, molecular modeling, differential scanning calorimetry, and polarization optical microscopy, allows one to establish the relationship between the shape of the structural unit (molecule or molecular aggregate), the nature of the interaction, and the phase behavior of the material.

Membrane behavior as influenced by partitioning of amphiphiles during drying : a comparative study in anhydrobiotic plant systems

NARCIS (Netherlands)

Golovina, E.A.; Hoekstra, F.A.

2002-01-01

During cellular desiccation, reduction in volume can in principle cause amphiphilic compounds to partition from the cytoplasm into membranes, with structural perturbance as the result. Here, we studied the effect of partitioning of endogenous amphiphiles on membrane surface dynamics in

Novel amphiphilic poly(dimethylsiloxane) based polyurethane networks tethered with carboxybetaine and their combined antibacterial and anti-adhesive property

Energy Technology Data Exchange (ETDEWEB)

Jiang, Jingxian; Fu, Yuchen; Zhang, Qinghua, E-mail: qhzhang@zju.edu.cn; Zhan, Xiaoli; Chen, Fengqiu

2017-08-01

Highlights: • An amphiphilic poly(dimethylsiloxane) (PDMS) based polyurethane (PU) network tethered with carboxybetaine is prepared. • The surface distribution of PDMS and zwitterionic segments produces an obvious amphiphilic heterogeneous surface. • This designed PDMS-based amphiphilic PU network exhibits combined antibacterial and anti-adhesive properties. - Abstract: The traditional nonfouling materials are powerless against bacterial cells attachment, while the hydrophobic bactericidal surfaces always suffer from nonspecific protein adsorption and dead bacterial cells accumulation. Here, amphiphilic polyurethane (PU) networks modified with poly(dimethylsiloxane) (PDMS) and cationic carboxybetaine diol through simple crosslinking reaction were developed, which had an antibacterial efficiency of 97.7%. Thereafter, the hydrolysis of carboxybetaine ester into zwitterionic groups brought about anti-adhesive properties against bacteria and proteins. The surface chemical composition and wettability performance of the PU network surfaces were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The surface distribution of PDMS and zwitterionic segments produced an obvious amphiphilic heterogeneous surface, which was demonstrated by atomic force microscopy (AFM). Enzyme-linked immunosorbent assays (ELISA) were used to test the nonspecific protein adsorption behaviors. With the advantages of the transition from excellent bactericidal performance to anti-adhesion and the combination of fouling resistance and fouling release property, the designed PDMS-based amphiphilic PU network shows great application potential in biomedical devices and marine facilities.

Parameters influencing the introduction of plasmid DNA into cells by the use of synthetic amphiphiles as a carrier system

OpenAIRE

van der Woude, Irene; Willy Visser, H.; ter Beest, Martin B.A.; Wagenaar, Anno; Ruiters, Marcel H.J.; Engberts, Jan B.F.N.; Hoekstra, Dick

1995-01-01

Parameters that affect cellular transfection as accomplished by introducing DNA via carriers composed of cationic synthetic amphiphiles, have been investigated with the aim to obtain insight into the mechanism of DNA translocation. Such insight may be exploited in optimizing carrier properties of synthetic amphiphiles for molecules other than nucleic acids. In the present work, the interaction of vesicles composed of the cationic amphiphile dioleyloxy-propyl-trimethylammonium chloride (DOTMA)...

Self-Assembled Amphiphilic Water Oxidation Catalysts: Control of O-O Bond Formation Pathways by Different Aggregation Patterns.

Science.gov (United States)

Yang, Bing; Jiang, Xin; Guo, Qing; Lei, Tao; Zhang, Li-Ping; Chen, Bin; Tung, Chen-Ho; Wu, Li-Zhu

2016-05-17

The oxidation of water to molecular oxygen is the key step to realize water splitting from both biological and chemical perspective. In an effort to understand how water oxidation occurs on a molecular level, a large number of molecular catalysts have been synthesized to find an easy access to higher oxidation states as well as their capacity to make O-O bond. However, most of them function in a mixture of organic solvent and water and the O-O bond formation pathway is still a subject of intense debate. Herein, we design the first amphiphilic Ru-bda (H2 bda=2,2'-bipyridine-6,6'-dicarboxylic acid) water oxidation catalysts (WOCs) of formula [Ru(II) (bda)(4-OTEG-pyridine)2 ] (1, OTEG=OCH2 CH2 OCH2 CH2 OCH3 ) and [Ru(II) (bda)(PySO3 Na)2 ] (2, PySO3 (-) =pyridine-3-sulfonate), which possess good solubility in water. Dynamic light scattering (DLS), scanning electron microscope (SEM), critical aggregation concentration (CAC) experiments and product analysis demonstrate that they enable to self-assemble in water and form the O-O bond through different routes even though they have the same bda(2-) backbone. This work illustrates for the first time that the O-O bond formation pathway can be regulated by the interaction of ancillary ligands at supramolecular level. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Analysis of supramolecular surface nanostructures using secondary ion mass spectrometry (poster)

International Nuclear Information System (INIS)

Halaszova, S.; Velic, D.

2013-01-01

Our system consists of host molecules β-cyclodextrin (C 42 H 70 O 35 ), of implemented Iron nanoparticles (guest). Whole supramolecular complex is placed on a gold substrate. In our project we work with monotiolated β-cyclodextrin (C 42 H 70 O 34 S), consisting of seven α-D-1-4 glucopyranose units. Cyclodextrins have been selected deliberately because of their ability to form inclusion complexes .They are also capable of forming structures similar to self-assembly monolayers. To study the formation of these supramolecular surface nanostructures mass secondary ion spectrometry is used. With this technique fragmentation of monotiolated β-cyclodextrin and the presence of the supramolecular complex on a gold surface can be examined. The observed fragments of monotiolated cyclodextrines films can be divided into three groups: Au X H Y S Z , fragments originating from cyclodextrin molecules associated with Au. Fragments as (C 42 H 70 O 34 S)Na + , (C 42 H 70 O 35 )Na + and (AuC 42 H 69 O 34 S)Na + were identified as well as fragments thereof in cationized form with K + . The main objective of the project is a detailed study and preparation of supramolecular nanostructures consisting of complex guest-host monotiolated β-cyclodextrin host-iron), and a gold substrate. (Authors)

Loading of Vesicles into Soft Amphiphilic Nanotubes using Osmosis

NARCIS (Netherlands)

Erne, Petra M.; van Bezouwen, Laura S.; Stacko, Peter; van Dtjken, Derk Jan; Chen, Jiawen; Stuart, Marc C. A.; Boekema, Eghert J.; Feringa, Ben L.

2015-01-01

The facile assembly of higher-order nanoarchitectures from simple building blocks is demonstrated by the loading of vesicles into soft amphiphilic nanotubes using osmosis. The nanotubes are constructed from rigid interdigitated bilayers which are capped with vesicles comprising phospholipid-based

Collaborative routes to clarifying the murky waters of aqueous supramolecular chemistry.

Science.gov (United States)

Cremer, Paul S; Flood, Amar H; Gibb, Bruce C; Mobley, David L

2017-12-19

On planet Earth, water is everywhere: the majority of the surface is covered with it; it is a key component of all life; its vapour and droplets fill the lower atmosphere; and even rocks contain it and undergo geomorphological changes because of it. A community of physical scientists largely drives studies of the chemistry of water and aqueous solutions, with expertise in biochemistry, spectroscopy and computer modelling. More recently, however, supramolecular chemists - with their expertise in macrocyclic synthesis and measuring supramolecular interactions - have renewed their interest in water-mediated non-covalent interactions. These two groups offer complementary expertise that, if harnessed, offer to accelerate our understanding of aqueous supramolecular chemistry and water writ large. This Review summarizes the state-of-the-art of the two fields, and highlights where there is latent chemical space for collaborative exploration by the two groups.

Collaborative routes to clarifying the murky waters of aqueous supramolecular chemistry

Science.gov (United States)

Cremer, Paul S.; Flood, Amar H.; Gibb, Bruce C.; Mobley, David L.

2018-01-01

On planet Earth, water is everywhere: the majority of the surface is covered with it; it is a key component of all life; its vapour and droplets fill the lower atmosphere; and even rocks contain it and undergo geomorphological changes because of it. A community of physical scientists largely drives studies of the chemistry of water and aqueous solutions, with expertise in biochemistry, spectroscopy and computer modelling. More recently, however, supramolecular chemists -- with their expertise in macrocyclic synthesis and measuring supramolecular interactions -- have renewed their interest in water-mediated non-covalent interactions. These two groups offer complementary expertise that, if harnessed, offer to accelerate our understanding of aqueous supramolecular chemistry and water writ large. This Review summarizes the state-of-the-art of the two fields, and highlights where there is latent chemical space for collaborative exploration by the two groups.

Single-component solid lipid nanocarriers prepared with ultra-long chain amphiphilic lipids

DEFF Research Database (Denmark)

Wei, Wei; Lu, Xiaonan; Wang, Zegao

2017-01-01

HYPOTHESIS: Synthetic sugar alcohol mono-behenates with high melting points, surface activity and resistance to enzymatic lipolysis, are expected to form stable single-component solid lipid nanocarriers (SC-SLNs). The preparation methods and the polar head group of the molecules should affect the......-probe sonication method had a micelle structure with fenofibrate incorporated into a lipid monolayer. This study provides an insight into the systematic development of novel amphiphilic lipids for solid lipid-based drug delivery system.......HYPOTHESIS: Synthetic sugar alcohol mono-behenates with high melting points, surface activity and resistance to enzymatic lipolysis, are expected to form stable single-component solid lipid nanocarriers (SC-SLNs). The preparation methods and the polar head group of the molecules should affect...... using the lipolysis model. The structure and drug distribution of the nanocarriers were studied using AFM and TEM. FINDINGS: Both the polar head group of the molecules and the preparation methods affect the particle size and size distribution. Nanocarriers prepared with sorbitol mono-behenates showed...

On the characterization of dynamic supramolecular systems: a general mathematical association model for linear supramolecular copolymers and application on a complex two-component hydrogen-bonding system.

Science.gov (United States)

Odille, Fabrice G J; Jónsson, Stefán; Stjernqvist, Susann; Rydén, Tobias; Wärnmark, Kenneth

2007-01-01

A general mathematical model for the characterization of the dynamic (kinetically labile) association of supramolecular assemblies in solution is presented. It is an extension of the equal K (EK) model by the stringent use of linear algebra to allow for the simultaneous presence of an unlimited number of different units in the resulting assemblies. It allows for the analysis of highly complex dynamic equilibrium systems in solution, including both supramolecular homo- and copolymers without the recourse to extensive approximations, in a field in which other analytical methods are difficult. The derived mathematical methodology makes it possible to analyze dynamic systems such as supramolecular copolymers regarding for instance the degree of polymerization, the distribution of a given monomer in different copolymers as well as its position in an aggregate. It is to date the only general means to characterize weak supramolecular systems. The model was fitted to NMR dilution titration data by using the program Matlab, and a detailed algorithm for the optimization of the different parameters has been developed. The methodology is applied to a case study, a hydrogen-bonded supramolecular system, salen 4+porphyrin 5. The system is formally a two-component system but in reality a three-component system. This results in a complex dynamic system in which all monomers are associated to each other by hydrogen bonding with different association constants, resulting in homo- and copolymers 4n5m as well as cyclic structures 6 and 7, in addition to free 4 and 5. The system was analyzed by extensive NMR dilution titrations at variable temperatures. All chemical shifts observed at different temperatures were used in the fitting to obtain the DeltaH degrees and DeltaS degrees values producing the best global fit. From the derived general mathematical expressions, system 4+5 could be characterized with respect to above-mentioned parameters.

The role of supramolecular chemistry in stimuli responsive and hierarchically structured functional organic materials

NARCIS (Netherlands)

Schenning, A.P.H.J.; Bastiaansen, C.W.M.; Broer, D.J.; Debije, M.G.

2014-01-01

ABSTRACT: In this review, we show the important role of supramolecular chemistry in the fabrication of stimuli responsive and hierarchically structured liquid crystalline polymer networks. Supramolecular interactions can be used to create three dimensional order or as molecular triggers in materials

An amphiphilic graft copolymer-based nanoparticle platform for reduction-responsive anticancer and antimalarial drug delivery

Science.gov (United States)

Najer, Adrian; Wu, Dalin; Nussbaumer, Martin G.; Schwertz, Geoffrey; Schwab, Anatol; Witschel, Matthias C.; Schäfer, Anja; Diederich, François; Rottmann, Matthias; Palivan, Cornelia G.; Beck, Hans-Peter; Meier, Wolfgang

2016-08-01

Medical applications of anticancer and antimalarial drugs often suffer from low aqueous solubility, high systemic toxicity, and metabolic instability. Smart nanocarrier-based drug delivery systems provide means of solving these problems at once. Herein, we present such a smart nanoparticle platform based on self-assembled, reduction-responsive amphiphilic graft copolymers, which were successfully synthesized through thiol-disulfide exchange reaction between thiolated hydrophilic block and pyridyl disulfide functionalized hydrophobic block. These amphiphilic graft copolymers self-assembled into nanoparticles with mean diameters of about 30-50 nm and readily incorporated hydrophobic guest molecules. Fluorescence correlation spectroscopy (FCS) was used to study nanoparticle stability and triggered release of a model compound in detail. Long-term colloidal stability and model compound retention within the nanoparticles was found when analyzed in cell media at body temperature. In contrast, rapid, complete reduction-triggered disassembly and model compound release was achieved within a physiological reducing environment. The synthesized copolymers revealed no intrinsic cellular toxicity up to 1 mg mL-1. Drug-loaded reduction-sensitive nanoparticles delivered a hydrophobic model anticancer drug (doxorubicin, DOX) to cancer cells (HeLa cells) and an experimental, metabolically unstable antimalarial drug (the serine hydroxymethyltransferase (SHMT) inhibitor (+/-)-1) to Plasmodium falciparum-infected red blood cells (iRBCs), with higher efficacy compared to similar, non-sensitive drug-loaded nanoparticles. These responsive copolymer-based nanoparticles represent a promising candidate as smart nanocarrier platform for various drugs to be applied to different diseases, due to the biocompatibility and biodegradability of the hydrophobic block, and the protein-repellent hydrophilic block.Medical applications of anticancer and antimalarial drugs often suffer from low aqueous

Stoichiometry-Controlled Inversion of Supramolecular Chirality in Nanostructures Co-assembled with Bipyridines.

Science.gov (United States)

Wang, Fang; Feng, Chuan-Liang

2018-02-01

To control supramolecular chirality of the co-assembled nanostructures, one of the remaining issues is how stoichiometry of the different molecules involved in co-assembly influence chiral transformation. Through co-assembly of achiral 1,4-bis(pyrid-4-yl)benzene and chiral phenylalanine-glycine derivative hydrogelators, stoichiometry is found to be an effective tool for controlling supramolecular chirality inversion processes. This inversion is mainly mediated by a delicate balance between intermolecular hydrogen bonding interactions and π-π stacking of the two components, which may subtly change the stacking of the molecules, in turn, the self-assembled nanostructures. This study exemplifies a simplistic way to invert the handedness of chiral nanostructures and provide fundamental understanding of the inherent principles of supramolecular chirality. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Supramolecular Nanostructures Based on Cyclodextrin and Poly(ethylene oxide: Syntheses, Structural Characterizations and Applications for Drug Delivery

Directory of Open Access Journals (Sweden)

Yue Zheng

2016-05-01

Full Text Available Cyclodextrins (CDs have been extensively studied as drug delivery carriers through host–guest interactions. CD-based poly(pseudorotaxanes, which are composed of one or more CD rings threading on the polymer chain with or without bulky groups (or stoppers, have attracted great interest in the development of supramolecular biomaterials. Poly(ethylene oxide (PEO is a water-soluble, biocompatible polymer. Depending on the molecular weight, PEO can be used as a plasticizer or as a toughening agent. Moreover, the hydrogels of PEO are also extensively studied because of their outstanding characteristics in biological drug delivery systems. These biomaterials based on CD and PEO for controlled drug delivery have received increasing attention in recent years. In this review, we summarize the recent progress in supramolecular architectures, focusing on poly(pseudorotaxanes, vesicles and supramolecular hydrogels based on CDs and PEO for drug delivery. Particular focus will be devoted to the structures and properties of supramolecular copolymers based on these materials as well as their use for the design and synthesis of supramolecular hydrogels. Moreover, the various applications of drug delivery techniques such as drug absorption, controlled release and drug targeting based CD/PEO supramolecular complexes, are also discussed.

Self-assembling peptide amphiphiles and related methods for growth factor delivery

Science.gov (United States)

Stupp, Samuel I [Chicago, IL; Donners, Jack J. J. M.; Silva, Gabriel A [Chicago, IL; Behanna, Heather A [Chicago, IL; Anthony, Shawn G [New Stanton, PA

2009-06-09

Amphiphilic peptide compounds comprising one or more epitope sequences for binding interaction with one or more corresponding growth factors, micellar assemblies of such compounds and related methods of use.

Driving forces for adsorption of amphiphilic peptides to the air-water interface.

Science.gov (United States)

Engin, Ozge; Villa, Alessandra; Sayar, Mehmet; Hess, Berk

2010-09-02

We have studied the partitioning of amphiphilic peptides at the air-water interface. The free energy of adsorption from bulk to interface was calculated by determining the potential of mean force via atomistic molecular dynamics simulations. To this end a method is introduced to restrain or constrain the center of mass of a group of molecules in a periodic system. The model amphiphilic peptides are composed of alternating valine and asparagine residues. The decomposition of the free energy difference between the bulk and interface is studied for different peptide block lengths. Our analysis revealed that for short amphiphilic peptides the surface driving force dominantly stems from the dehydration of hydrophobic side chains. The only opposing force is associated with the loss of orientational freedom of the peptide at the interface. For the peptides studied, the free energy difference scales linearly with the size of the molecule, since the peptides mainly adopt extended conformations both in bulk and at the interface. The free energy difference depends strongly on the water model, which can be rationalized through the hydration thermodynamics of hydrophobic solutes. Finally, we measured the reduction of the surface tension associated with complete coverage of the interface with peptides.

Size-controlled and redox-responsive supramolecular nanoparticles

NARCIS (Netherlands)

Weinhart-Mejia, R.; Kronig, G.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

Synthesis, Characterization, and Aqueous Lubricating Properties of Amphiphilic Graft Copolymers Comprising 2-Methoxyethyl Acrylate

DEFF Research Database (Denmark)

Javakhishvili, Irakli; Røn, Troels; Jankova Atanasova, Katja

2014-01-01

Amphiphilic anionic and cationic graft copolymers possessing poly(2-hydroxyethyl methacrylate) (PHEMA) backbone and poly(methacrylic acid), poly(2-methoxyethyl acrylate-co-methacrylic acid), and poly(2-methoxyethyl acrylate-co-2-(dimethylamino)ethyl methacrylate) grafts are constructed by merging...... of the corresponding monomers followed by deblocking reaction leads to well-defined amphiphiles with narrow molecular weight distributions (PDI ≤ 1.29) and varying content of methacrylic acid. The graft copolymers showed effective surface adsorption and lubrication for self-mated poly(dimethylsiloxane) (PDMS) contacts...

A polyamidoamine dendrimer-streptavidin supramolecular architecture for biosensor development.

Science.gov (United States)

Soda, N; Arotiba, O A

2017-12-01

A novel polyamidoamine dendrimer-streptavidin supramolecular architecture suitable as a versatile platform for biosensor development is reported. The dendrimer was electrodeposited on a glassy carbon electrode via cyclic voltammetry. The dendrimer electrode was further modified with streptavidin by electrostatic attraction upon drop coating. The platform i.e. the dendrimer-streptavidin modified electrode was electrochemically interrogated in phosphate buffer, ferrocyanide and H 2 O 2 . The dendrimer-streptavidin platform was used in the preparation of a simple DNA biosensor as a proof of concept. The supramolecular architecture of dendrimer-streptavidin was stable, electroactive and thus lends itself as a versatile immobilisation layer for any biotinylated bioreceptors in biosensor development. Copyright © 2017 Elsevier B.V. All rights reserved.

Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

KAUST Repository

Shi, Junfeng; Yuan, Dan; Haburcak, Richard; Zhang, Qiang; Zhao, Chao; Zhang, Xixiang; Xu, Bing

2015-01-01

Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

KAUST Repository

Shi, Junfeng

2015-10-14

Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

Supra-molecular Association and Polymorphic Behaviour In Systems Containing Bile Acid Salts

Directory of Open Access Journals (Sweden)

Camillo La Mesa

2007-08-01

Full Text Available A wide number of supra-molecular association modes are observed in mixtures containing water and bile salts, BS, (with, eventually, other components. Molecular or micellar solutions transform into hydrated solids, fibres, lyotropic liquid crystals and/or gels by raising the concentration, the temperature, adding electrolytes, surfactants, lipids and proteins. Amorphous or ordered phases may be formed accordingly. The forces responsible for this very rich polymorphism presumably arise from the unusual combination of electrostatic, hydrophobic and hydrogen-bond contributions to the system stability, with subsequent control of the supra-molecular organisation modes. The stabilising effect due to hydrogen bonds does not occur in almost all surfactants or lipids and is peculiar to bile acids and salts. Some supra-molecular organisation modes, supposed to be related to malfunctions and dis-metabolic diseases in vivo, are briefly reported and discussed.

Cellular uptake: lessons from supramolecular organic chemistry.

Science.gov (United States)

Gasparini, Giulio; Bang, Eun-Kyoung; Montenegro, Javier; Matile, Stefan

2015-07-04

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.

Fabrication of Supramolecular Chirality from Achiral Molecules at the Liquid/Liquid Interface Studied by Second Harmonic Generation.

Science.gov (United States)

Lin, Lu; Zhang, Zhen; Guo, Yuan; Liu, Minghua

2018-01-09

We present the investigation into the supramolecular chirality of 5-octadecyloxy-2-(2-pyridylazo)phenol (PARC18) at water/1,2-dichloroethane interface by second harmonic generation (SHG). We observe that PARC18 molecules form supramolecular chirality through self-assembly at the liquid/liquid interface although they are achiral molecules. The bulk concentration of PARC18 in the organic phase has profound effects on the supramolecular chirality. By increasing bulk concentration, the enantiomeric excess at the interface first grows and then decreases until it eventually vanishes. Further analysis reveals that the enantiomeric excess is determined by the twist angle of PARC18 molecules at the interface rather than their orientational angle. At lower and higher bulk concentrations, the average twist angle of PARC18 molecules approaches zero, and the assemblies are achiral; whereas at medium bulk concentrations, the average twist angle is nonzero, so that the assemblies show supramolecular chirality. We also estimate the coverage of PARC18 molecules at the interface versus the bulk concentration and fit it to Langmuir adsorption model. The result indicates that PARC18 assemblies show strongest supramolecular chirality in a half-full monolayer. These findings highlight the opportunities for precise control of supramolecular chirality at liquid/liquid interfaces by manipulating the bulk concentration.

Minimalistic peptide supramolecular co-assembly: expanding the conformational space for nanotechnology.

Science.gov (United States)

Makam, Pandeeswar; Gazit, Ehud

2018-05-21

Molecular self-assembly is a ubiquitous process in nature and central to bottom-up nanotechnology. In particular, the organization of peptide building blocks into ordered supramolecular structures has gained much interest due to the unique properties of the products, including biocompatibility, chemical and structural diversity, robustness and ease of large-scale synthesis. In addition, peptides, as short as dipeptides, contain all the molecular information needed to spontaneously form well-ordered structures at both the nano- and the micro-scale. Therefore, peptide supramolecular assembly has been effectively utilized to produce novel materials with tailored properties for various applications in the fields of material science, engineering, medicine, and biology. To further expand the conformational space of peptide assemblies in terms of structural and functional complexity, multicomponent (two or more) peptide supramolecular co-assembly has recently evolved as a promising extended approach, similar to the structural diversity of natural sequence-defined biopolymers (proteins) as well as of synthetic covalent co-polymers. The use of this methodology was recently demonstrated in various applications, such as nanostructure physical dimension control, the creation of non-canonical complex topologies, mechanical strength modulation, the design of light harvesting soft materials, fabrication of electrically conducting devices, induced fluorescence, enzymatic catalysis and tissue engineering. In light of these significant advancements in the field of peptide supramolecular co-assembly in the last few years, in this tutorial review, we provide an updated overview and future prospects of this emerging subject.

Zwitterionic supramolecular nanoparticles: self-assembly and responsive properties

NARCIS (Netherlands)

Stoffelen, C.; Huskens, Jurriaan

2015-01-01

Supramolecular nanoparticles (SNPs) are of high interest in both nanoscience and molecular diagnostics and therapeutics, because of their reversible and designable properties. To ensure colloidal stabilization and biocompatibility, most reported strategies require the use of hydrophilic long-chain

Fragrance compounds and amphiphilic association structures.

Science.gov (United States)

Friberg, S E

1998-05-01

Fragrance formulations have traditionally been based on alcohol as the solvent, but the recent legal restrictions on volatile organic solvents have prompted the industry to change to aqueous solubilized systems. The article reviews the fundamental factors in the application of such systems evaluating the influence by different amphiphilic association structures on the vapor pressure of fragrance compounds. This information is subsequently used to estimate the variation of fragrance compound vapor pressures during evaporation. The results reveal that the vapor pressure versus time variation is improved compared to solvent-based formulations.

Natural supramolecular building blocks: from virus coat proteins to viral nanoparticles.

Science.gov (United States)

Liu, Zhi; Qiao, Jing; Niu, Zhongwei; Wang, Qian

2012-09-21

Viruses belong to a fascinating class of natural supramolecular structures, composed of multiple copies of coat proteins (CPs) that assemble into different shapes with a variety of sizes from tens to hundreds of nanometres. Because of their advantages including simple/economic production, well-defined structural features, unique shapes and sizes, genetic programmability and robust chemistries, recently viruses and virus-like nanoparticles (VLPs) have been used widely in biomedical applications and materials synthesis. In this critical review, we highlight recent advances in the use of virus coat proteins (VCPs) and viral nanoparticles (VNPs) as building blocks in self-assembly studies and materials development. We first discuss the self-assembly of VCPs into VLPs, which can efficiently incorporate a variety of different materials as cores inside the viral protein shells. Then, the self-assembly of VNPs at surfaces or interfaces is summarized. Finally, we discuss the co-assembly of VNPs with different functional materials (178 references).

Langmuir monolayer formation of metal complexes from polymerizable amphiphilic ligands

NARCIS (Netherlands)

Werkman, P.J; Schouten, A.J.

1996-01-01

The monolayer behaviour of 4-(10,12-pentacosadiynoicamidomethyl)-pyridine at the air-water interface was studied by measuring the surface pressure-area isotherms. The amphiphile formed stable monolayers with a clear liquid-expanded (LE) to liquid-condensed phase transition at various temperatures.

Improved glucose-neopentyl glycol (GNG) amphiphiles for membrane protein solubilization and stabilization.

Science.gov (United States)

Cho, Kyung Ho; Bae, Hyoung Eun; Das, Manabendra; Gellman, Samuel H; Chae, Pil Seok

2014-02-01

Membrane proteins are inherently amphipathic and undergo dynamic conformational changes for proper function within native membranes. Maintaining the functional structures of these biomacromolecules in aqueous media is necessary for structural studies but difficult to achieve with currently available tools, thus necessitating the development of novel agents with favorable properties. This study introduces several new glucose-neopentyl glycol (GNG) amphiphiles and reveals some agents that display favorable behaviors for the solubilization and stabilization of a large, multi-subunit membrane protein assembly. Furthermore, a detergent structure-property relationship that could serve as a useful guideline for the design of novel amphiphiles is discussed. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assemblage and post-radiation recovery of cell supramolecular structures

International Nuclear Information System (INIS)

Grodzinskij, D.M.; Kolomiets, K.D.

1979-01-01

The role of the molecular equation and self-assemblage in post-radiation chromatin recovery of meristematic cells of pea rootlets is shown. Found are the two repair types at the chromatin level by fractionating of the radiation dose. The first type comprises transient processes including DNA repair, the second type comprises processes including biosynthesis of the chromatin components and proteins, in the first place. The role of protein biosynthesis in the process of recovery of the chromatin supramolecular structure is shown. The improved radiostability of chromatin self-assemblage is characteristic for the level of its subunits. The supramolecular chromatin structure of the other levels has less radiostability

Self-assembly of a supramolecular square between [Ni(dppe(TOF2] and 4,4'-Bipyridine

Directory of Open Access Journals (Sweden)

Paulo Torres

2013-08-01

Full Text Available The main interest of this research is to contribute to the development and understanding of supramolecular chemistry and molecular architectures, which are constructed by the self-assembly of supramolecular entities. Therefore, the synthesis and characterization (IR, UV, 1H NMR, 31P, 19F, 1H-1H COSY of a nickel (II supramolecular square [7] was performed through the synthesis between nickel chloride [1] and diphenylphosphinoethane (dppe [2] to form the precursor complex [Ni(dppeCl2] [3]. This was followed by the synthesis of the complex of interest, [Ni(dppe(TOF2] [5], using the precursor and silver trifluoromethanesulfonate (Ag-TOF. Finally, the self-assembly was performed between the complex [1,2-bis(diphenylphosphinoethanebistriflatonickel(II] [Ni(dppe(OSO2CF32] [5] and the organic ligand 4,4'-bipyridine [6], which act as vertex and edge, respectively.According to various analyses, it was found that the self-assembly generated only one supramolecular species; a square is the most probable thermodynamic structure.

Terpene and dextran renewable resources for the synthesis of amphiphilic biopolymers.

Science.gov (United States)

Alvès, Marie-Hélène; Sfeir, Huda; Tranchant, Jean-François; Gombart, Emilie; Sagorin, Gilles; Caillol, Sylvain; Billon, Laurent; Save, Maud

2014-01-13

The present work shows the synthesis of amphiphilic polymers based on the hydrophilic dextran and the hydrophobic terpenes as renewable resources. The first step concerns the synthesis of functional terpene molecules by thiol-ene addition chemistry involving amino or carboxylic acid thiols and dihydromyrcenol terpene. The terpene-modified polysaccharides were subsequently synthesized by coupling the functional terpenes with dextran. A reductive amination step produced terpene end-modified dextran with 94% of functionalization, while the esterification step produced three terpene-grafted dextrans with a number of terpene units per dextran of 1, 5, and 10. The amphiphilic renewable grafted polymers were tested as emulsifiers for the stabilization of liquid miniemulsion of terpene droplets dispersed in an aqueous phase. The average hydrodynamic diameter of the stable droplets was observed at about 330 nm.

Intra-chain organisation of hydrophobic residues controls inter-chain aggregation rates of amphiphilic polymers

Science.gov (United States)

Varilly, Patrick; Willard, Adam P.; Kirkegaard, Julius B.; Knowles, Tuomas P. J.; Chandler, David

2017-04-01

Aggregation of amphiphiles through the action of hydrophobic interactions is a common feature in soft condensed matter systems and is of particular importance in the context of biophysics as it underlies both the generation of functional biological machinery as well as the formation of pathological misassembled states of proteins. Here we explore the aggregation behaviour of amphiphilic polymers using lattice Monte Carlo calculations and show that the distribution of hydrophobic residues within the polymer sequence determines the facility with which dry/wet interfaces can be created and that such interfaces drive the aggregation process.

Physical deposition behavior of stiff amphiphilic polyelectrolytes in an external electric field

Science.gov (United States)

Hu, Dongmei; Zuo, Chuncheng; Cao, Qianqian; Chen, Hongli

2017-08-01

Coarse-grained molecular dynamics simulations are conducted to study the physical deposition behavior of stiff amphiphilic polyelectrolytes (APEs) in an external electric field. The effects of chain stiffness, the charge distribution of a hydrophilic block, and electric field strength are investigated. Amphiphilic multilayers, which consist of a monolayer of adsorbed hydrophilic monomers (HLMs), a hydrophobic layer, and another hydrophilic layer, are formed in a selective solvent. All cases exhibit locally ordered hydrophilic monolayers. Two kinds of hydrophobic micelles are distinguished based on local structures. Stripe and network hydrophobic patterns are formed in individual cases. Increasing the chain stiffness decreases the thickness of the deposited layer, the lateral size of the hydrophobic micelles, and the amount of deposition. Increasing the number of positively charged HLMs in a single chain has the same effect as increasing chain stiffness. Moreover, when applied normally to the substrate, the electric field compresses the deposited structures and increases the amount of deposition by pulling more PEs toward the substrate. A stronger electric field also facilitates the formation of a thinner and more ordered hydrophilic adsorption layer. These estimates help us explore how to tailor patterned nano-surfaces, nano-interfaces, or amphiphilic nanostructures by physically depositing semi-flexible APEs which is of crucial importance in physical sciences, life sciences and nanotechnology.

Injectable self-healing carboxymethyl chitosan-zinc supramolecular hydrogels and their antibacterial activity.

Science.gov (United States)

Wahid, Fazli; Zhou, Ya-Ning; Wang, Hai-Song; Wan, Tong; Zhong, Cheng; Chu, Li-Qiang

2018-04-07

Injectable and self-healing hydrogels have found numerous applications in drug delivery, tissue engineering and 3D cell culture. Herein, we report an injectable self-healing carboxymethyl chitosan (CMCh) supramolecular hydrogels cross-linked by zinc ions (Zn 2+ ). Supramolecular hydrogels were obtained by simple addition of metal ions solution to CMCh solution at an appropriate pH value. The mechanical properties of these hydrogels were adjustable by the concentration of Zn 2+ . For example, the hydrogel with the highest concentration of Zn 2+ (CMCh-Zn4) showed strongest mechanical properties (storage modulus~11,000Pa) while hydrogel with the lowest concentration of Zn 2+ (CMCh-Zn1) showed weakest mechanical properties (storage modulus~220Pa). As observed visually and confirmed rheologically, the CMCh-Zn1 hydrogel with the lowest Zn 2+ concentration showed thixotropic property. CMCh-Zn1 hydrogel also presented injectable property. Moreover, the antibacterial properties of the prepared supramolecular hydrogels were studied against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) by agar well diffusion method. The results revealed Zn 2+ dependent antibacterial properties against both kinds of strains. The inhibition zones were ranging from ~11-24mm and ~10-22mm against S. aureus and E. coli, respectively. We believe that the prepared supramolecular hydrogels could be used as a potential candidate in biomedical fields. Copyright © 2018 Elsevier B.V. All rights reserved.

Preparation and self-folding of amphiphilic DNA origami.

Science.gov (United States)

Zhou, Chao; Wang, Dianming; Dong, Yuanchen; Xin, Ling; Sun, Yawei; Yang, Zhongqiang; Liu, Dongsheng

2015-03-01

Amphiphilic DNA origami is prepared by dressing multiple hydrophobic molecules on a rectangular single layer DNA origami, which is then folded or coupled in sandwich-like structures with two outer DNA origami layer and one inner hydrophobic molecules layer. The preference to form different kinds of structures could be tailored by rational design of DNA origami. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular Host-Guest System as Ratiometric Fe3+ Ion Sensor Based on Water-Soluble Pillar[5]arene.

Science.gov (United States)

Yao, Qianfang; Lü, Baozhong; Ji, Chendong; Cai, Yang; Yin, Meizhen

2017-10-18

Developing a specific, ratiometric, and reversible detection method for metal ions is significant to guard against the threat of metal-caused environmental pollution and organisms poisoning. Here a supramolecular host-guest system (WP5⊃G) based on water-soluble pillar[5]arene (WP5) and water-soluble quaternized perylene diimide derivative (G) was constructed. Morphological transformation was achieved during the process of adding WP5 into G aqueous solution, and a fluorescence "turn-off" phenomenon was observed which was caused by supramolecular photoinduced electron transfer (PET). Meanwhile, hydrophobic effect and electrostatic interaction played important roles in this supramolecular process, which was confirmed by isothermal titration calorimeter (ITC) and ζ potential experiments. Furthermore, the supramolecular host-guest system could be a "turn-on" fluorescent probe for Fe 3+ ion detection through the process of interdicting supramolecular PET. Moreover, the Fe 3+ ion detection showed specific, ratiometric, and reversible performances with a detection limit of 2.13 × 10 -7 M, which might have great potentials in biological and environmental monitoring.

On the slowdown mechanism of water dynamics around small amphiphiles

NARCIS (Netherlands)

Homsi Brandeburgo, W.; Thijmen van der Post, S.; Meijer, E.J.; Ensing, B.

2015-01-01

Aqueous solvation of small amphiphilic molecules exhibits a unique and complex dynamics, that is only partially understood. A recent series of studies on the hydration of small organic compounds, such as tetramethylurea (TMU), trimethylamine N-oxide (TMAO) and urea, has provided strong evidence of a

Conformational properties of rigid-chain amphiphilic macromolecules : The phase diagram

NARCIS (Netherlands)

Markov, V. A.; Vasilevskaya, V. V.; Khalatur, P. G.; ten Brinke, G.; Khokhlov, A. R.

The coil-globule transition in rigid-chain amphiphilic macromolecules was studied by means of computer simulation, and the phase diagrams for such molecules in the solvent quality-persistence length coordinates were constructed. It was shown that the type of phase diagram depends to a substantial

Evaporation rate-based selection of supramolecular chirality.

Science.gov (United States)

Hattori, Shingo; Vandendriessche, Stefaan; Koeckelberghs, Guy; Verbiest, Thierry; Ishii, Kazuyuki

2017-03-09

We demonstrate the evaporation rate-based selection of supramolecular chirality for the first time. P-type aggregates prepared by fast evaporation, and M-type aggregates prepared by slow evaporation are kinetic and thermodynamic products under dynamic reaction conditions, respectively. These findings provide a novel solution reaction chemistry under the dynamic reaction conditions.

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

In vitro Plasmodium falciparum drug sensitivity assay: inhibition of parasite growth by incorporation of stomatocytogenic amphiphiles into the erythrocyte membrane

DEFF Research Database (Denmark)

Ziegler, Hanne L; Staerk, Dan; Christensen, Jette

2002-01-01

Lupeol, which shows in vitro inhibitory activity against Plasmodium falciparum 3D7 strain with a 50% inhibitory concentration (IC50) of 27.7 +/- 0.5 microM, was shown to cause a transformation of the human erythrocyte shape toward that of stomatocytes. Good correlation between the IC50 value...... culture continued to grow well in untreated erythrocytes. Thus, the antiplasmodial activity of lupeol appears to be indirect, being due to stomatocytic transformation of the host cell membrane and not to toxic effects via action on a drug target within the parasite. A number of amphiphiles that cause...... for development of new antimalarial drugs, care must be exercised in the interpretation of results of screening of plant extracts and natural product libraries by an in vitro Plasmodium toxicity assay....

Glucosamine-Based Supramolecular Nanotubes for Human Mesenchymal Cell Therapy.

Science.gov (United States)

Talloj, Satish Kumar; Cheng, Bill; Weng, Jen-Po; Lin, Hsin-Chieh

2018-04-23

Herein, we demonstrate an example of glucosamine-based supramolecular hydrogels that can be used for human mesenchymal cell therapy. We designed and synthesized a series of amino acid derivatives based on a strategy of capping d-glucosamine moiety at the C-terminus and fluorinated benzyl group at the N-terminus. From a systematic study on chemical structures, we discovered that the glucosamine-based supramolecular hydrogel [pentafluorobenzyl (PFB)-F-Glu] self-assembled with one-dimensional nanotubular structures at physiological pH. The self-assembly of a newly discovered PFB-F-Glu motif is attributed to the synergistic effect of π-π stacking and extensive intermolecular hydrogen bonding network in aqueous medium. Notably, PFB-F-Glu nanotubes are proven to be nontoxic to human mesenchymal stem cells (hMSCs) and have been shown to enhance hMSC proliferation while maintaining their pluripotency. Retaining of pluripotency capabilities provides potentially unlimited source of undifferentiated cells for the treatment of future cell therapies. Furthermore, hMSCs cultured on PFB-F-Glu are able to secrete paracrine factors that downregulate profibrotic gene expression in lipopolysaccharide-treated human skin fibroblasts, which demonstrates that PFB-F-Glu nanotubes have the potential to be used for wound healing applications. Overall, this article addresses the importance of chemical design to generate supramolecular biomaterials for stem cell therapy.

Supramolecular structures constructed from three novel rare earth ...

Indian Academy of Sciences (India)

Supramolecular structures constructed from three novel rare earth metal complexes. HUAZE DONGa,∗, XIAOJUN FENGb,∗, XIA LIUc, BIN ZHENGa, JIANHONG BIa, YAN XUEa,. SHAOHUA GOUd and YANPING WANGa. aDepartment of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China.

Chiral Binaphthylbis(4,4'-Bipyridin-1-Ium)/Cucurbit[8]Uril Supramolecular System and Its Induced Circularly Polarized Luminescence.

Science.gov (United States)

Chen, Xu-Man; Chen, Yong; Liang, Lu; Liu, Qiu-Jun; Liu, Yu

2018-05-01

Circularly polarized luminescence (CPL) induced by host-guest complexation remains a challenge in supramolecular chemistry. Herein, a couple of CPL-silent enantiomeric guest binaphthylbis(4,4'-bipyridinium) salts can emit obvious CPL in the presence of cucurbit[8]uril in aqueous media, due to the restriction of molecular rotation limitation effect. Such CPL can be reversibly adjusted by the addition of acid and base. Furthermore, the resultant supramolecular systems can interact with DNA, accompanied by the morphological conversion from branched supramolecular nanowires to exfoliated nanowires, which can enable to the exploration of such supramolecular systems as DNA markers by CPL signals. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular Derivation of Graphene Nanomaterials for Chemical Sensors

DEFF Research Database (Denmark)

Olsen, Gunnar

With properties such as high surface area, high conductivity, and low production cost with easy up-scaling, graphene-like materials provide a promising support for many applications, one of which is for chemical sensors. By functionalization with molecular receptors such as supramolecular moieties...... of 10−5 M. In the second approach Azido-RGO was prepared as a general platform for post reduction modification. GO was here functionalized with a short linker terminated in an alcohol. The intermediate material was then reduced effectively with NaBH4, followed by chemical transformation of the alcohol...... atoms or slightly more than one azide per nm2 of RGO-sheet. This Azido-RGO was used in successful functionalization with the large supramolecular receptor molecules TTF-calix[4]pyrrole which function as a sensor for Cl− and potentially for TNB. The coverage achieved was one molecule per 50 – 60 carbon...

Host-Guest Interaction between Corona[n]arene and Bisquaternary Ammonium Derivatives for Fabricating Supra-Amphiphile.

Science.gov (United States)

Zeng, Lingda; Guo, Qing-Hui; Feng, Yuanning; Xu, Jiang-Fei; Wei, Yuhan; Li, Zhibo; Wang, Mei-Xiang; Zhang, Xi

2017-06-13

The interactions between a host, water-soluble corona[n]arene (S6-CAP), and a series of guests, bisquaternary ammonium derivatives (CnDAs), in water, were investigated. The host and guest can form 1:1 host-guest complex. Their binding constants decrease as the alkyl length of CnDAs increases, which can be tunable ranging from 10 3 to 10 6 M -1 . The binding processes are mainly entropy-driven, while the enthalpy changes also play an important role in enhancing the host-guest interactions. In addition, a supra-amphiphile was fabricated with S6-CAP and a normal surfactant bearing bisquaternary ammonium (C4R). The S6-CAP·C4R complex forms micellar aggregates in water, and the system possesses better assembling activity and dilution stability than its building block C4R. This study enriches the families of supra-amphiphiles with a new architecture, and employing such a supra-amphiphile in biofunctional materials is highly anticipated.

Steering Self-Assembly of Amphiphilic Molecular Nanostructures via Halogen Exchange

NARCIS (Netherlands)

Kriete, Björn; Bondarenko, Anna S.; Jumde, Varsha R.; Franken, Linda E.; Minnaard, Adriaan J.; Jansen, Thomas L. C.; Knoester, Jasper; Pshenichnikov, Maxim S.

2017-01-01

In the field of self-assembly, the quest for gaining control over the supramolecular architecture without affecting the functionality of the individual molecular building blocks is intrinsically challenging. By using a combination of synthetic chemistry, cryogenic transmission electron microscopy,

Optical characterization of CdS nanoparticles embedded into the comb-type amphiphilic graft copolymer

Science.gov (United States)

Kalaycı, Özlem A.; Duygulu, Özgür; Hazer, Baki

2013-01-01

This study refers to the synthesis and characterization of a novel organic/inorganic hybrid nanocomposite material containing cadmium sulfide (CdS) nanoparticles. For this purpose, a series of polypropylene (PP)-g-polyethylene glycol (PEG), PP-g-PEG comb-type amphiphilic graft copolymers were synthesized. PEGs with Mn = 400, 2000, 3350, and 8000 Da were used and the graft copolymers obtained were coded as PPEG400, PPEG2000, PPEG3350, and PPEG8000. CdS nanoparticles were formed in tetrahydrofuran solution of PP-g-PEG amphiphilic comb-type copolymer by the reaction between aqueous solutions of Na2S and Cd(CH3COO)2 simultaneously. Micelle formation of PPEG2000 comb-type amphiphilic graft copolymer in both solvent/non-solvent (petroleum ether-THF) by transmission electron microscopy (TEM). The optical characteristics, size morphology, phase analysis, and dispersion of CdS nanoparticles embedded in PPEG400, PPEG2000, PPEG3350, and PPEG8000 comb-type amphiphilic graft copolymer micelles were determined by high resolution TEM (HRTEM), energy dispersive spectroscopy, UV-vis spectroscopy, and fluorescence emission spectroscopy techniques. The aggregate size of PPEG2000-CdS is between 10 and 50 nm; however, in the case of PPEG400-CdS, PPEG3350-CdS, and PPEG8000-CdS samples, it is up to approximately 100 nm. The size of CdS quantum dots in the aggregates for PPEG2000 and PPEG8000 samples was observed as 5 nm by HRTEM analysis, and this result was also supported by UV-vis absorbance spectra and fluorescence emission spectra.

Optical characterization of CdS nanoparticles embedded into the comb-type amphiphilic graft copolymer

Energy Technology Data Exchange (ETDEWEB)

Kalayc Latin-Small-Letter-Dotless-I , Oezlem A. [Bulent Ecevit University, Department of Physics (Turkey); Duygulu, Oezguer [TUBITAK Marmara Research Center, Materials Institute (Turkey); Hazer, Baki, E-mail: bkhazer@karaelmas.edu.tr [Bulent Ecevit University, Department of Chemistry (Turkey)

2013-01-15

This study refers to the synthesis and characterization of a novel organic/inorganic hybrid nanocomposite material containing cadmium sulfide (CdS) nanoparticles. For this purpose, a series of polypropylene (PP)-g-polyethylene glycol (PEG), PP-g-PEG comb-type amphiphilic graft copolymers were synthesized. PEGs with Mn = 400, 2000, 3350, and 8000 Da were used and the graft copolymers obtained were coded as PPEG400, PPEG2000, PPEG3350, and PPEG8000. CdS nanoparticles were formed in tetrahydrofuran solution of PP-g-PEG amphiphilic comb-type copolymer by the reaction between aqueous solutions of Na{sub 2}S and Cd(CH{sub 3}COO){sub 2} simultaneously. Micelle formation of PPEG2000 comb-type amphiphilic graft copolymer in both solvent/non-solvent (petroleum ether-THF) by transmission electron microscopy (TEM). The optical characteristics, size morphology, phase analysis, and dispersion of CdS nanoparticles embedded in PPEG400, PPEG2000, PPEG3350, and PPEG8000 comb-type amphiphilic graft copolymer micelles were determined by high resolution TEM (HRTEM), energy dispersive spectroscopy, UV-vis spectroscopy, and fluorescence emission spectroscopy techniques. The aggregate size of PPEG2000-CdS is between 10 and 50 nm; however, in the case of PPEG400-CdS, PPEG3350-CdS, and PPEG8000-CdS samples, it is up to approximately 100 nm. The size of CdS quantum dots in the aggregates for PPEG2000 and PPEG8000 samples was observed as 5 nm by HRTEM analysis, and this result was also supported by UV-vis absorbance spectra and fluorescence emission spectra.

Optical characterization of CdS nanoparticles embedded into the comb-type amphiphilic graft copolymer

International Nuclear Information System (INIS)

Kalaycı, Özlem A.; Duygulu, Özgür; Hazer, Baki

2013-01-01

This study refers to the synthesis and characterization of a novel organic/inorganic hybrid nanocomposite material containing cadmium sulfide (CdS) nanoparticles. For this purpose, a series of polypropylene (PP)-g-polyethylene glycol (PEG), PP-g-PEG comb-type amphiphilic graft copolymers were synthesized. PEGs with Mn = 400, 2000, 3350, and 8000 Da were used and the graft copolymers obtained were coded as PPEG400, PPEG2000, PPEG3350, and PPEG8000. CdS nanoparticles were formed in tetrahydrofuran solution of PP-g-PEG amphiphilic comb-type copolymer by the reaction between aqueous solutions of Na 2 S and Cd(CH 3 COO) 2 simultaneously. Micelle formation of PPEG2000 comb-type amphiphilic graft copolymer in both solvent/non-solvent (petroleum ether–THF) by transmission electron microscopy (TEM). The optical characteristics, size morphology, phase analysis, and dispersion of CdS nanoparticles embedded in PPEG400, PPEG2000, PPEG3350, and PPEG8000 comb-type amphiphilic graft copolymer micelles were determined by high resolution TEM (HRTEM), energy dispersive spectroscopy, UV–vis spectroscopy, and fluorescence emission spectroscopy techniques. The aggregate size of PPEG2000-CdS is between 10 and 50 nm; however, in the case of PPEG400-CdS, PPEG3350-CdS, and PPEG8000-CdS samples, it is up to approximately 100 nm. The size of CdS quantum dots in the aggregates for PPEG2000 and PPEG8000 samples was observed as 5 nm by HRTEM analysis, and this result was also supported by UV–vis absorbance spectra and fluorescence emission spectra.

Metal-Ion-Mediated Supramolecular Chirality of l-Phenylalanine Based Hydrogels.

Science.gov (United States)

Wang, Fang; Feng, Chuan-Liang

2018-05-14

For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l-phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular solubilization of fullerenes and radio-fullerenes in aqueous media

International Nuclear Information System (INIS)

Braun, T.

1999-01-01

In this paper we are dealing with the supramolecular complexation of fullerenes C 60 , C 70 , some functionalized fullerenes and of the dumbbell structured C 120 dimer, with two host molecules, namely γ-cyclo-dextrin (GCD), and sulfocalix[8]arene in order to make them soluble in water. Previous investigations by others have shown that the reactions of some mentioned fullerenes and cyclo-dextrins and calixarenes are very slow and tedious in liquid phase as a result of solvatation effects. That we have decided to pursue the supramolecular complexation as solid-solid reactions by using mechanochemical activation in a ball mill. A mechanochemical treatment was used to enhance chemical reactivity in solid-solid reactions in which GCD give a complex with the C 60 as 2:1 host-guest complex. The calix[8]arene complex with C 60 molecule has been prepared. The sulfonated form of the host is well soluble in water. Endohedral radio-fullerenes of the XandC60 type (where * X is a rare gas, e.g. Ar, Xe, Kr, radionuclide) were prepared by nuclear recoil after neutron irradiation, a method developed by the author The endohedrally labelled fullerenes were then mechanochemically complexed into a labelled supramolecular complex with cyclo-dextrin and calixarene hosts. (author)

Supramolecular Liquid Crystal Displays Construction and Applications

OpenAIRE

Hoogboom, J.T.V.

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 post-LCD construction. In addition, the thesis describes the application of LCD technology in biosensors.

ANIONIC SYNTHESIS OF A "CLICKABLE" MIDDLE-CHAIN AZIDEFUNCTIONALIZED POLYSTYRENE AND ITS APPLICATION IN SHAPE AMPHIPHILES

Institute of Scientific and Technical Information of China (English)

Kan Yue; Jinlin He; Chang Liu; Mingjun Huang; Xue-Hui Dong; Kai Guo; Peihong Ni

2013-01-01

"Click chemistry" is,by definition,a general functionalization methodology (GFM) and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis.This paper reports the synthesis of a "clickable" middle-chain azide-functionalized polystyrene (mPS-N3) by anionic polymerization and its application in the preparation of novel shape amphiphiles based on polyhedral oligomeric silsesquioxane (POSS).The mPS-N3 was synthesized by coupling living poly(styryl)lithium chains (PSLi) with 3-chloropropylmethyldichlorosilane and subsequent nucleophilic substitution of the chloro group in the presence of sodium azide.Excess PSLi was end-capped with ethylene oxide to facilitate its removal by flash chromatography.The mPS-N3 was then derived into a giant lipid-like shape amphiphile in two steps following a sequential "click" strategy.The copper(I)-catalyzed azide-alkyne cycloaddition between mPS-N3 and alkyne-functionalized vinyl-substituted POSS derivative (VPOSS-alkyne) ensured quantitative ligation to give polystyrene with VPOSS tethered at the middle of the chain (mPS-VPOSS).The thiol-ene reaction with 1-thioglycerol transforms the vinyl groups on the POSS periphery to hydroxyls,resulting in an amphiphilic shape amphiphile,mPS-DPOSS.This synthetic approach is highly efficient and modular.It demonstrates the "click" philosophy of facile complex molecule construction from a library of simple building blocks and also suggests that mPS-N3 can be used as a versatile "clickable" motif in polymer science for the precise synthesis of complex macromolecules.

Cylindrical micelles of a POSS amphiphilic dendrimer as nano-reactors for polymerization.

Science.gov (United States)

Weng, Jing-Ting; Yeh, Tso-Fan; Samuel, Ashok Zachariah; Huang, Yi-Fan; Sie, Jyun-Hao; Wu, Kuan-Yi; Peng, Chi-How; Hamaguchi, Hiro-O; Wang, Chien-Lung

2018-02-15

A low generation amphiphilic dendrimer, POSS-AD, which has a POSS core and eight amphiphilic arms, was synthesized and used as a nano-reactor to produce well-defined polymer nano-cylinders. Confirmed by small-angle X-ray scattering (SAXS), Raman and NMR spectrometry, monodispersed cylindrical micelles that contain a hydrophilic cavity with a diameter of 2.09 nm and a length of 4.26 nm were produced via co-assembling POSS-AD with hydrophilic liquids, such as H 2 O and HEMA in hydrophobic solvents. Taking the HEMA/POSS-AD cylindrical micelles as nano-reactors, polymerization of HEMA within the micelles results in polymer nano-cylinders (POSS-ADNPs) with a diameter of 2.24 nm and a length of 5.02 nm. The study confirmed that despite the inability to maintain specific shape in solution, low generation dendrimers form well-defined nano-containers or nano-reactors, which relies on co-assembling with hydrophilic guest molecules. These nano-reactors are robust enough to maintain their shape during the polymerization of the guest molecules. Polymer nano-cylinders with dimensions less than 10 nm can thus be produced from the HEMA/POSS-AD micelles. Since the chemical structure of low-generation dendrimers and the contents of the co-assembled nano-reactors can be easily adjusted, the concept holds the potential for the further developments of low-generation amphiphilic dendrimers.

Amphiphilic carbon dots for sensitive detection, intracellular imaging of Al{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Kong, Depeng [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Yan, Fanyong, E-mail: yanfanyong@tjpu.edu.cn [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Luo, Yunmei [Department of Pharmacology/Key Laboratory for Basic Pharmacology of Ministry of Education, Zunyi Medical College, Guizhou 563000 (China); Ye, Qianghua; Zhou, Siyushan [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China); Chen, Li, E-mail: Chenlis@tjpu.edu.cn [State Key Laboratory of Separation Membranes and Membrane Processes, School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

2017-02-08

In this paper, a simple and effective method was designed to synthesize hydrophobic carbon dots. Subsequently, amphiphilic fluorescent carbon dots (A-CDs) were synthesized by further surface modification. The result A-CDs show excellent optical properties with a quantum yield of 16.9%. It was interestingly found that morin (MR) and its fluorescent metal-ion complex (MR-Al{sup 3+}) can successfully coordinate on the surface of A-CDs, the emission of A-CDs completely overlapped the absorption peak of MR-Al{sup 3+}. Thus, the prepared A-CDs can be used as an effective fluorescent probe for Al{sup 3+} based on a fluorescence resonance energy transfer process. The sensing platform can realize real-time detection of Al{sup 3+} within 0.5 min. The fluorescence signals of the system were linearly correlated with the concentration of Al{sup 3+} over a range of 8–20 μM, with a detection limit of 0.113 μM. The method was also successfully applied to image the distribution of Al{sup 3+} in Human Umbilical Vein Endothelial Cells. - Highlights: • Amphiphilic carbon dots were obtained by simply modifying hydrophobic carbon dots. • Amphiphilic carbon dots/morin-Al{sup 3+} was used as a selective turn-on probe for Al{sup 3+}. • The method was employed to intracellular imaging Al{sup 3+} in living cells.

A Dynamic Supramolecular System Exhibiting Substrate Selectivity in the Catalytic Epoxidation of Olefins

DEFF Research Database (Denmark)

Jonsson, Stefan; Odille, Fabrice G. J.; Norrby, Per-Ola

2005-01-01

A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction.......A dynamic supramolecular system involving hydrogen bonding between a Mn(III) salen catalyst and a Zn(II) porphyrin receptor exhibits selectivity for pyridine appended cis-beta-substituted styrene derivatives over phenyl appended derivatives in a catalytic epoxidation reaction....

Strong supramolecular control over protein self-assembly using a polyamine decorated β-cyclodextrin as synthetic recognition element

NARCIS (Netherlands)

Uhlenheuer, D.A.; Milroy, L.G.; Neirynck, P.; Brunsveld, L.

2011-01-01

The supramolecular host molecule heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-ß-cyclodextrin provides strong control over protein self-assembly in synthetic supramolecular protein constructs. Mono-functionalization of this modified ß-cyclodextrin with a cysteine residue allows for site-selective

Amphiphile Meets Amphiphile: Beyond the Polar-Apolar Dualism in Ionic Liquid/Alcohol Mixtures.

Science.gov (United States)

Russina, Olga; Sferrazza, Alessio; Caminiti, Ruggero; Triolo, Alessandro

2014-05-15

The mesoscopic morphology of binary mixtures of ethylammonium nitrate (EAN), the protic ionic liquid par excellence, and methanol is explored using neutron/X-ray diffraction and computational techniques. Both compounds are amphiphilic and characterized by an extended hydrogen bonding network: surprisingly, though macroscopically homogeneous, these mixtures turn out to be mesoscopically highly heterogeneous. Our study reveals that even in methanol-rich mixtures, a wide distribution of clusters exists where EAN preserves its bulk, sponge-like morphology. Accordingly methanol does not succeed in fully dissociating the ionic liquid that keeps on organizing in a bulk-like fashion. This behavior represents the premises to the more dramatic phenomenology observed with longer alcohols that eventually phase separate from EAN. These results challenge the commonly accepted polar and apolar moieties segregation in ionic liquids/molecular liquids mixtures and the current understanding of technologically relevant solvation processes.

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.

Formation and thermodynamic stability of (polymer + porphyrin) supramolecular structures in aqueous solutions

International Nuclear Information System (INIS)

Costa, Viviana C.P. da; Hwang, Barrington J.; Eggen, Spencer E.; Wallace, Megan J.; Annunziata, Onofrio

2014-01-01

Highlights: • Thermodynamic stability of a (polymer + porphyrin) supramolecular structure was characterized. • Isothermal titration calorimetry provided two ways to determine reaction enthalpies. • Exothermic (polymer + porphyrin) binding competes with porphyrin self-association. • (Polymer + porphyrin) binding is entropically favored with respect to porphyrin self-association. • Spectral shifts show importance of porphyrin central hydrogens in polymer binding. - Abstract: Optical properties of porphyrins can be tuned through (polymer + porphyrin) (host + guest) binding in solution. This gives rise to the formation of supramolecular structures. In this paper, the formation, thermodynamic stability and spectroscopic properties of (polymer + porphyrin) supramolecular structures and their competition with porphyrin self-association were investigated by both isothermal titration calorimetry (ITC) and absorption spectroscopy. Specifically, reaction enthalpies and equilibrium constants were measured for meso-tetrakis(4-sulfonatophenyl) porphyrin (TPPS) self-association and TPPS binding to the polymer poly(vinylpyrrolidone) (PVP, 40 kg/mol) in aqueous solutions at pH 7 and three different temperatures (12, 25 and 37 °C). ITC, compared to spectroscopic techniques, provides two independent means to determine reaction enthalpies: direct measurements and Van’t Hoff plot. This was used as a criterion to assess that (1) self-association of TPPS is limited to the formation of dimers and (2) TPPS binds to PVP in its monomeric state only. The formation of TPPS dimers and (PVP + TPPS) supramolecular structures are both enthalpically driven. However, (polymer + porphyrin) binding was found to be entropically favored compared to dimerization. Furthermore, the reaction enthalpies of these two processes significantly depend on temperature. This behavior was attributed to hydrophobic interactions. Finally, the limiting absorption spectra of monomeric, dimeric and polymer

[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.

A new configurational bias scheme for sampling supramolecular structures

Energy Technology Data Exchange (ETDEWEB)

De Gernier, Robin; Mognetti, Bortolo M., E-mail: bmognett@ulb.ac.be [Center for Nonlinear Phenomena and Complex Systems, Université Libre de Bruxelles, Code Postal 231, Campus Plaine, B-1050 Brussels (Belgium); Curk, Tine [Department of Chemistry, University of Cambridge, Cambridge CB2 1EW (United Kingdom); Dubacheva, Galina V. [Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia - San Sebastian (Spain); Richter, Ralf P. [Biosurfaces Unit, CIC biomaGUNE, Paseo Miramon 182, 20009 Donostia - San Sebastian (Spain); Université Grenoble Alpes, DCM, 38000 Grenoble (France); CNRS, DCM, 38000 Grenoble (France); Max Planck Institute for Intelligent Systems, 70569 Stuttgart (Germany)

2014-12-28

We present a new simulation scheme which allows an efficient sampling of reconfigurable supramolecular structures made of polymeric constructs functionalized by reactive binding sites. The algorithm is based on the configurational bias scheme of Siepmann and Frenkel and is powered by the possibility of changing the topology of the supramolecular network by a non-local Monte Carlo algorithm. Such a plan is accomplished by a multi-scale modelling that merges coarse-grained simulations, describing the typical polymer conformations, with experimental results accounting for free energy terms involved in the reactions of the active sites. We test the new algorithm for a system of DNA coated colloids for which we compute the hybridisation free energy cost associated to the binding of tethered single stranded DNAs terminated by short sequences of complementary nucleotides. In order to demonstrate the versatility of our method, we also consider polymers functionalized by receptors that bind a surface decorated by ligands. In particular, we compute the density of states of adsorbed polymers as a function of the number of ligand–receptor complexes formed. Such a quantity can be used to study the conformational properties of adsorbed polymers useful when engineering adsorption with tailored properties. We successfully compare the results with the predictions of a mean field theory. We believe that the proposed method will be a useful tool to investigate supramolecular structures resulting from direct interactions between functionalized polymers for which efficient numerical methodologies of investigation are still lacking.

Design and application of cationic amphiphilic β-cyclodextrin derivatives as gene delivery vectors

Science.gov (United States)

Wan, Ning; Huan, Meng-Lei; Ma, Xi-Xi; Jing, Zi-Wei; Zhang, Ya-Xuan; Li, Chen; Zhou, Si-Yuan; Zhang, Bang-Le

2017-11-01

The nano self-assembly profiles of amphiphilic gene delivery vectors could improve the density of local cationic head groups to promote their DNA condensation capability and enhance the interaction between cell membrane and hydrophobic tails, thus increasing cellular uptake and gene transfection. In this paper, two series of cationic amphiphilic β-cyclodextrin (β-CD) derivatives were designed and synthesized by using 6-mono-OTs-β-CD (1) as the precursor to construct amphiphilic gene vectors with different building blocks in a selective and controlled manner. The effect of different type and degree of cationic head groups on transfection and the endocytic mechanism of β-CD derivatives/DNA nanocomplexes were also investigated. The results demonstrated that the designed β-cyclodextrin derivatives were able to compact DNA to form stable nanocomplexes and exhibited low cytotoxicity. Among them, PEI-1 with PEI head group showed enhanced transfection activity, significantly higher than commercially available agent PEI25000 especially in the presence of serum, showing potential application prospects in clinical trials. Moreover, the endocytic uptake mechanism involved in the gene transfection of PEI-1 was mainly through caveolae-mediated endocytosis, which could avoid the lysosomal degradation of loaded gene, and had great importance for improving gene transfection activity.

New penta-saccharide-bearing tripod amphiphiles for membrane protein structure studies

DEFF Research Database (Denmark)

Ehsan, Muhammad; Ghani, Lubna; Du, Yang

2017-01-01

of detergents, are available, purification and structural characterization of many membrane proteins remain challenging. In the current study, a new class of tripod amphiphiles bearing two different penta-saccharide head groups, designated TPSs, were developed and evaluated for their ability to extract...

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.

Direct investigation of the vectorization properties of amphiphilic cyclodextrins in phospholipid films.

Science.gov (United States)

Javierre, Isabelle; Nedyalkov, Mickael; Petkova, Vera; Benattar, Jean Jacques; Weisse, Sandrine; Auzély-Velty, Rachel; Djedaïni-Pilard, Florence; Perly, Bruno

2002-10-01

Recently, new cyclodextrin derivatives were synthesized and shown to exhibit strong amphiphilic properties. In this paper, we study the action of these new amphiphilic cyclodextrins on phospholipids. Mixed phospholipid/cyclodextrin derivative films were prepared and studied using X-ray reflectivity for various phospholipid/cyclodextrin ratios. A molar ratio of 3 provides a highly stable film the molecular structure of which has been investigated in detail. The cholesterol tail of the cyclodextrin molecule was found to be anchored into the phospholipid film. The cyclodextrin moieties exposed to the aqueous medium are prone to the addition of the guest molecule Dosulepin, making them of high interest for drug delivery. For this purpose and as an example of a potential application, this cyclodextrin molecular carrier property is also addressed to this complex film architecture.

A Water-Soluble Cyclotriveratrylene-Based Supra-amphiphile: Synthesis, pH-Responsive Self-Assembly in Water, and Its Application in Controlled Drug Release.

Science.gov (United States)

Xia, Danyu; Li, Yang; Jie, Kecheng; Shi, Bingbing; Yao, Yong

2016-06-17

A new water-soluble cyclotriveratrylene (WCTV) was designed and synthesized, and benzyldimethyldodecylammonium chloride (G) was chosen as the guest molecule to construct a supra-amphiphile by the host-guest interaction between WCTV and G in water, which is pH responsive. The supra-amphiphiles self-assembled into vesicles in water. When the pH of the solution was below 7.0, the supra-amphiphile disassociated, and the vesicles collapsed. Then, the pH-responsive self-assembly system was utilized for controlled drug release.

Coassembly of Lysozyme and Amphiphilic Biomolecules Driven by Unimer-Aggregate Equilibrium.

Science.gov (United States)

Tao, Yuanyuan; Ma, Xiaoteng; Cai, Yaqian; Liu, Li; Zhao, Hanying

2018-04-12

Synthesis and self-assembly of bioconjugates composed of proteins and synthetic molecules have been widely studied because of the potential applications in medicine, biotechnology, and nanotechnology. One of the challenging research studies in this area is to develop organic solvent-free approaches to the synthesis and self-assembly of amphiphilic bioconjugates. In this research, dialysis-assisted approach, a method based on unimer-aggregate equilibrium, was applied in the coassembly of lysozyme and conjugate of cholesterol and glutathione (Ch-GSH). In phosphate buffer solution, amphiphilic Ch-GSH conjugate self-assembles into vesicles, and the vesicle solution is dialyzed against lysozyme solution. Negatively charged Ch-GSH unimers produced in the unimer-vesicle exchange equilibrium, diffuse across the dialysis membrane and have electrostatic interaction with positively charged lysozyme, resulting in the formation of Ch-GSH-lysozyme bioconjugate. Above a critical concentration, the three-component bioconjugate molecules self-assemble into bioactive vesicles.

A theoretical study of colloidal forces near an amphiphilic polymer brush

Science.gov (United States)

Wu, Jianzhong

2011-03-01

Polymer-based ``non-stick'' coatings are promising as the next generation of effective, environmentally-friendly marine antifouling systems that minimize nonspecific adsorption of extracellular polymeric substances (EPS). However, design and development of such systems are impeded by the poor knowledge of polymer-mediated interactions of biomacromolecules with the protected substrate. In this work, a polymer density functional theory (DFT) is used to predict the potential of mean force between spherical biomacromolecules and amphiphilic copolymer brushes within a coarse-grained model that captures essential nonspecific interactions such as the molecular excluded volume effects and the hydrophobic energies. The relevance of theoretical results for practical control of the EPS adsorption is discussed in terms of the efficiency of different brush configurations to prevent biofouling. It is shown that the most effective antifouling surface may be accomplished by using amphiphilic brushes with a long hydrophilic backbone and a hydrophobic end at moderate grafting density.

Engineering with macromolecules : from supramolecular chemistry to defined nanomaterials

NARCIS (Netherlands)

Lohmeijer, B.G.G.; Gohy, J.M.W.; Schubert, U.S.

2003-01-01

By uniting concepts from polymer chem. and supramol. chem. we present a new approach for the prepn. of functional nano-materials. Amphiphilic diblock and triblock copolymers were constructed in such a way that a bisterpyridine ruthenium complex acts as the linker between the two constituting blocks.

HPMA-based block copolymers promote differential drug delivery kinetics for hydrophobic and amphiphilic molecules.

Science.gov (United States)

Tomcin, Stephanie; Kelsch, Annette; Staff, Roland H; Landfester, Katharina; Zentel, Rudolf; Mailänder, Volker

2016-04-15

We describe a method how polymeric nanoparticles stabilized with (2-hydroxypropyl)methacrylamide (HPMA)-based block copolymers are used as drug delivery systems for a fast release of hydrophobic and a controlled release of an amphiphilic molecule. The versatile method of the miniemulsion solvent-evaporation technique was used to prepare polystyrene (PS) as well as poly-d/l-lactide (PDLLA) nanoparticles. Covalently bound or physically adsorbed fluorescent dyes labeled the particles' core and their block copolymer corona. Confocal laser scanning microscopy (CLSM) in combination with flow cytometry measurements were applied to demonstrate the burst release of a fluorescent hydrophobic drug model without the necessity of nanoparticle uptake. In addition, CLSM studies and quantitative calculations using the image processing program Volocity® show the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake. Our findings offer the possibility to combine the advantages of a fast release for hydrophobic and a controlled release for an amphiphilic molecule therefore pointing to the possibility to a 'multi-step and multi-site' targeting by one nanocarrier. We describe thoroughly how different components of a nanocarrier end up in cells. This enables different cargos of a nanocarrier having a consecutive release and delivery of distinct components. Most interestingly we demonstrate individual kinetics of distinct components of such a system: first the release of a fluorescent hydrophobic drug model at contact with the cell membrane without the necessity of nanoparticle uptake. Secondly, the intracellular detachment of the amphiphilic block copolymer from the particles' core after uptake occurs. This offers the possibility to combine the advantages of a fast release for a hydrophobic substance at the time of interaction of the nanoparticle with the cell surface and a controlled release for an amphiphilic molecule later on therefore

Shape Recovery with Concomitant Mechanical Strengthening of Amphiphilic Shape Memory Polymers in Warm Water

International Nuclear Information System (INIS)

Zhang, Ben; DeBartolo, Janae E.; Song, Jie

2017-01-01

Maintaining adequate or enhancing mechanical properties of shape memory polymers (SMPs) after shape recovery in an aqueous environment are greatly desired for biomedical applications of SMPs as self-fitting tissue scaffolds or minimally invasive surgical implants. Here we report stable temporary shape fixing and facile shape recovery of biodegradable triblock amphiphilic SMPs containing a poly(ethylene glycol) (PEG) center block and flanking poly(lactic acid) or poly(lactic-co-glycolic acid) blocks in warm water, accompanied with concomitant enhanced mechanical strengths. Differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WXRD) and small-angle X-ray scattering (SAXS) analyses revealed that the unique stiffening of the amphiphilic SMPs upon hydration was due to hydration-driven microphase separation and PEG crystallization. We further demonstrated that the chemical composition of degradable blocks in these SMPs could be tailored to affect the persistence of hydration-induced stiffening upon subsequent dehydration. These properties combined open new horizons for these amphiphilic SMPs for smart weight-bearing in vivo applications (e.g. as self-fitting intervertebral discs). In conclusion, this study also provides a new material design strategy to strengthen polymers in aqueous environment in general.

Self-Assembled Nanocarriers Based on Amphiphilic Natural Polymers for Anti- Cancer Drug Delivery Applications.

Science.gov (United States)

Sabra, Sally; Abdelmoneem, Mona; Abdelwakil, Mahmoud; Mabrouk, Moustafa Taha; Anwar, Doaa; Mohamed, Rania; Khattab, Sherine; Bekhit, Adnan; Elkhodairy, Kadria; Freag, May; Elzoghby, Ahmed

2017-01-01

Micellization provides numerous merits for the delivery of water insoluble anti-cancer therapeutic agents including a nanosized 'core-shell' drug delivery system. Recently, hydrophobically-modified polysaccharides and proteins are attracting much attention as micelle forming polymers to entrap poorly soluble anti-cancer drugs. By virtue of their small size, the self-assembled micelles can passively target tumor tissues via enhanced permeation and retention effect (EPR). Moreover, the amphiphilic micelles can be exploited for active-targeted drug delivery by attaching specific targeting ligands to the outer micellar hydrophilic surface. Here, we review the conjugation techniques, drug loading methods, physicochemical characteristics of the most important amphiphilic polysaccharides and proteins used as anti-cancer drug delivery systems. Attention focuses on the mechanisms of tumor-targeting and enhanced anti-tumor efficacy of the encapsulated drugs. This review will highlight the remarkable advances of hydrophobized polysaccharide and protein micelles and their potential applications as anti-cancer drug delivery nanosystems. Micellar nanocarriers fabricated from amphiphilic natural polymers hold great promise as vehicles for anti-cancer drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Supramolecular nanofibers of triamcinolone acetonide for uveitis therapy

Science.gov (United States)

Li, Xingyi; Wang, Yuqin; Yang, Chengbiao; Shi, Shuai; Jin, Ling; Luo, Zichao; Yu, Jing; Zhang, Zhaoliang; Yang, Zhimou; Chen, Hao

2014-11-01

Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular compatibility in rats, as indicated by the optical coherence tomography (OCT) images, HE observation, and glial fibrillary acidic protein (GFAP) and vimentin immuno-staining assays of the retinas. Our TA hydrogel showed a decreased efficacy to inhibit ocular inflammation in the rat's experiment autoimmune uveitis (EAU) model compared to the commercial TA suspension (Transton®), but without causing complications such as high intraocular pressure and cataracts. These promising properties of the hydrogel indicated its great potential for the treatment of eye diseases.Supramolecular nanofibers of prodrugs hold advantages for drug release due to their high drug payload, sustained and constant drug release behavior, and stimuli responsiveness. In this study, we report on a supramolecular hydrogel mainly formed by a clinically used drug triamcinolone acetonide (TA). Such a hydrogel could only be prepared via an ester bond hydrolysis process from its prodrug of succinated triamcinolone acetonide (STA). The resulting hydrogel could constantly release TA in the in vitro release experiment. The TA hydrogel possessed an excellent transscleral penetration ability, as evaluated by the in vitro transscleral transport study. The developed TA hydrogel also exhibited a great ocular

Reversible optical transcription of supramolecular chirality into molecular chirality

NARCIS (Netherlands)

Jong, Jaap J.D. de; Lucas, Linda N.; Kellogg, Richard M.; Esch, Jan H. van; Feringa, Bernard

2004-01-01

In nature, key molecular processes such as communication, replication, and enzyme catalysis all rely on a delicate balance between molecular and supramolecular chirality. Here we report the design, synthesis, and operation of a reversible, photoresponsive, self-assembling molecular system in which

Switchable charge injection barrier in an organic supramolecular semiconductor

NARCIS (Netherlands)

Gorbunov, A.V.; Haedler, A.T.; Putzeys, T.; Zha, R.H.; Schmidt, H.W.; Kivala, M.; Urbanavičiutec, I.; Wübbenhorst, M.; Meijer, E.W.; Kemerink, M.

2016-01-01

We disclose a supramolecular material that combines semiconducting and dipolar functionalities. The material consists of a discotic semiconducting carbonyl-bridged triarylamine core, which is surrounded by three dipolar amide groups. In thin films, the material self-organizes in a hexagonal columnar

Rotation of a single molecule within a supramolecular bearing

DEFF Research Database (Denmark)

Gimzewski, J.K.; Joachim, C.; Schlittler, R.R.

1998-01-01

Experimental visualization and verification of a single-molecule rotor operating within a supramolecular bearing is reported. Using a scanning tunneling microscope, single molecules were observed to exist in one of two spatially defined states Laterally separated by 0.26 nanometers. One...

Supramolecular organization and chiral resolution of p-terphenyl-m-dicarbonitrile on the Ag(111) surface.

Science.gov (United States)

Marschall, Matthias; Reichert, Joachim; Seufert, Knud; Auwärter, Willi; Klappenberger, Florian; Weber-Bargioni, Alexander; Klyatskaya, Svetlana; Zoppellaro, Giorgio; Nefedov, Alexei; Strunskus, Thomas; Wöll, Christof; Ruben, Mario; Barth, Johannes V

2010-05-17

The supramolecular organization and layer formation of the non-linear, prochiral molecule [1, 1';4',1'']-terphenyl-3,3"-dicarbonitrile adsorbed on the Ag(111) surface is investigated by scanning tunneling microscopy (STM) and near-edge X-ray absorption fine-structure spectroscopy (NEXAFS). Upon two-dimensional confinement the molecules are deconvoluted in three stereoisomers, that is, two mirror-symmetric trans- and one cis-species. STM measurements reveal large and regular islands following room temperature deposition, whereby NEXAFS confirms a flat adsorption geometry with the electronic pi-system parallel to the surface plane. The ordering within the expressed supramolecular arrays reflects a substrate templating effect, steric constraints and the operation of weak lateral interactions mainly originating from the carbonitrile endgroups. High-resolution data at room temperature reveal enantiormorphic characteristics of the molecular packing schemes in different domains of the arrays, indicative of chiral resolution during the 2D molecular self-assembly process. At submonolayer coverage supramolecular islands coexist with a disordered fluid phase of highly mobile molecules. Following thermal quenching (down to 6 K) we find extended supramolecular ribbons stabilised again by attractive and directional noncovalent interactions, the formation of which reflects a chiral resolution of trans-species.

Thermo-reversible supramolecular hydrogels of trehalose-type diblock methylcellulose analogues.

Science.gov (United States)

Yamagami, Mao; Kamitakahara, Hiroshi; Yoshinaga, Arata; Takano, Toshiyuki

2018-03-01

This paper describes the design and synthesis of new trehalose-type diblock methylcellulose analogues with nonionic, cationic, and anionic cellobiosyl segments, namely 1-(tri-O-methyl-cellulosyl)-4-[β-d-glucopyranosyl-(1→4)-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (1), 1-(tri-O-methyl-cellulosyl)-4-[(6-amino-6-deoxy-β-d-glucopyranosyl)-(1→4)- 6-amino-6-deoxy-β-d-glucopyranosyloxymethyl]-1H-1,2,3-triazole (2), and 4-(tri-O-methyl-cellulosyloxymethyl)-1-[β-d-glucopyranuronosyl-(1→4)-β-d-glucopyranuronosyl]-1H-1,2,3-triazole (3), respectively. Aqueous solutions of all of the 1,2,3-triazole-linked diblock methylcellulose analogues possessed higher surface activities than that of industrially produced methylcellulose and exhibited lower critical solution temperatures, that allowed the formation of thermoresponsive supramolecular hydrogels at close to human body temperature. Supramolecular structures of thermo-reversible hydrogels based on compounds 1, 2, and 3 were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Detailed structure-property-function relationships of compounds 1, 2, and 3 were discussed. Not only nonionic hydrophilic segment but also ionic hydrophilic segments of diblock methylcellulose analogues were valid for the formation of thermo-reversible supramolecular hydrogels based on end-functionalized methylcellulose. Copyright © 2017 Elsevier Ltd. All rights reserved.

New carbon-carbon linked amphiphilic carboranyl-porphyrins as boron neutron capture agents

International Nuclear Information System (INIS)

Vicente, M.G.H.; Wickramasinghe, A.; Shetty, S.J.; Smith, K.M.

2000-01-01

Novel amphiphilic carboranyl-porphyrins have been synthesized for Boron Neutron Capture Therapy (BNCT). These compounds have carbon-carbon bonds between the carborane residues and the porphyrin meso-phenyl groups, and contain 28-31% boron by weight . (author)

Block versus Random Amphiphilic Glycopolymer Nanopaticles as Glucose-Responsive Vehicles.

Science.gov (United States)

Guo, Qianqian; Zhang, Tianqi; An, Jinxia; Wu, Zhongming; Zhao, Yu; Dai, Xiaomei; Zhang, Xinge; Li, Chaoxing

2015-10-12

To explore the effect of polymer structure on their self-assembled aggregates and their unique characteristics, this study was devoted to developing a series of amphiphilic block and random phenylboronic acid-based glycopolymers by RAFT polymerization. The amphiphilic glycopolymers were successfully self-assembled into spherically shaped nanoparticles with narrow size distribution in aqueous solution. For block and random copolymers with similar monomer compositions, block copolymer nanoparticles exhibited a more regular transmittance change with the increasing glucose level, while a more evident variation of size and quicker decreasing tendency in I/I0 behavior in different glucose media were observed for random copolymer nanoparticles. Cell viability of all the polymer nanoparticles investigated by MTT assay was higher than 80%, indicating that both block and random copolymers had good cytocompatibility. Insulin could be encapsulated into both nanoparticles, and insulin release rate for random glycopolymer was slightly quicker than that for the block ones. We speculate that different chain conformations between block and random glycopolymers play an important role in self-assembled nanoaggregates and underlying glucose-sensitive behavior.

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.

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.

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

[Supramolecular Agents for Theranostics].

Science.gov (United States)

Deyev, S M; Lebedenko, E N

2015-01-01

This mini-review summarizes recent data obtained in the process of creation of a versatile module platform suitable for construction of supramolecular theranostic agents. As an example, we consider multifunctional hybrid agents for imaging and elimination of cancer cells. The use of an adapter protein system barnase:barstar for producing targeted multifunctional hybrid structures on the basis of highly specific peptides and mini-antibodies as addressing modules and recombinant proteins and/or nanoparticles of different nature (quantum dots, nanogold, magnetic nanoparticles, nanodiamonds, upconverting nanophosphores, polymer nanoparticles) as agents visualizing and damaging cancer cells is described. New perspectives for creation of selective and highly effective compounds for theranostics and personified medicine are contemplated.

Triblock Copolymers with Grafted Fluorine-Free Amphiphilic Non-Ionic Side Chains for Antifouling and Fouling-Release Applications

Energy Technology Data Exchange (ETDEWEB)

Y Cho; H Sundaram; C Weinman; M Paik; M Dimitriou; J Finlay; M Callow; J Callow; E Kramer; C Ober

2011-12-31

Fluorine-free, amphiphilic, nonionic surface active block copolymers (SABCs) were synthesized through chemical modification of a polystyrene-block-poly(ethylene-ran-butylene)-block-polyisoprene triblock copolymer precursor with selected amphiphilic nonionic Brij and other surfactants. Amphiphilicity was imparted by a hydrophobic aliphatic group combined with a hydrophilic poly(ethylene glycol) (PEG) group-containing moiety. The surfaces were characterized by dynamic water contact angle, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure (NEXAFS) analysis. In biofouling assays, settlement (attachment) of both spores of the green alga Ulva and cells of the diatom Navicula on SABCs modified with Brij nonionic side chains was significantly reduced relative to a PDMS standard, with a nonionic surfactant combining a PEG group and an aliphatic moiety demonstrating the best performance. Additionally, a fouling-release assay using sporelings (young plants) of Ulva and Navicula suggested that the SABC derived from nonionic Brij side chains also out-performed PDMS as a fouling-release material. Good antifouling and fouling-release properties were not demonstrated for the other two amphiphilic surfaces derived from silicone and aromatic group containing nonionic surfactants included in this study. The results suggest that small differences in chemical surface functionality impart more significant changes with respect to the antifouling settlement and fouling-release performance of materials than overall wettability behavior.

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

KAUST Repository

Wang, Shuang; Zhao, Tingting; Li, Guanghua; Wojtas, Łukasz; Huo, Qisheng; Eddaoudi, Mohamed; Liu, Yunling

2010-01-01

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

Supramolecular Cocrystals of Gliclazide: Synthesis, Characterization and Evaluation.

Science.gov (United States)

Chadha, Renu; Rani, Dimpy; Goyal, Parnika

2017-03-01

To prepare the supramolecular cocrystals of gliclazide (GL, a BCS class II drug molecule) via mechanochemical route, with the goal of improving physicochemical and biopharmaceutical properties. Two cocrystals of GL with GRAS status coformers, sebacic acid (GL-SB; 1:1) and α-hydroxyacetic acid (GL-HA; 1:1) were screened out using liquid assisted grinding. The prepared cocrystals were characterized using thermal and analytical techniques followed by evaluation of antidiabetic activity and pharmacokinetic parameters. The generation of new, single and pure crystal forms was characterized by DSC and PXRD. The crystal structure determination from PXRD revealed the existence of both cocrystals in triclinic (P-1) crystal system. The hydrogen bonded network, determined by material studio was well supported by shifts in FTIR and SSNMR. Both the new solid forms displayed improved solubility, IDR, antidiabetic activity and pharmacokinetic parameters as compared to GL. The improvement in these physicochemical and biopharmaceutical properties corroborated the fact that the supramolecular cocrystallization may be useful in the development of pharmaceutical crystalline materials with interesting network and properties.

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.

Synthesis of amphiphilic aminated inulin via 'click chemistry' and evaluation for its antibacterial activity.

Science.gov (United States)

Dong, Fang; Zhang, Jun; Yu, Chunwei; Li, Qing; Ren, Jianming; Wang, Gang; Gu, Guodong; Guo, Zhanyong

2014-09-15

Inulins are a group of abundant, water-soluble, renewable polysaccharides, which exhibit attractive bioactivities and natural properties. Improvement such as chemical modification of inulin is often performed prior to further utilization. We hereby presented a method to modify inulin at its primary hydroxyls to synthesize amphiphilic aminated inulin via 'click chemistry' to facilitate its chemical manipulation. Additionally, its antibacterial property against Staphylococcus aureus (S. aureus) was also evaluated and the best inhibitory index against S. aureus was 58% at 1mg/mL. As the amphiphilic aminated inulin is easy to prepare and exhibits improved bioactivity, this material may represent as an attractive new platform for chemical modifications of inulin. Copyright © 2014 Elsevier Ltd. All rights reserved.

Epoxy resin-inspired reconfigurable supramolecular networks

OpenAIRE

Balkenende Diederik; Olson Rebecca; Balog Sandor; Weder Christoph; Montero de Espinosa Lucas

2016-01-01

With the goal to push the mechanical properties of reconfigurable supramolecular polymers toward those of thermoset resins we prepared and investigated a new family of hydrogen bonded polymer networks that are assembled from isophthalic acid terminated oligo(bisphenol A co epichlorohydrin) and different bipyridines. These materials display high storage moduli of up to 3.9 GPa can be disassembled upon heating to form melts with a viscosity of as low as 2.1 Pa·s and fully reassemble upon coolin...

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.

Rational design of fiber forming supramolecular structures

Science.gov (United States)

Wang, Benjamin K; Kanahara, Satoko M

2016-01-01

Recent strides in the development of multifunctional synthetic biomimetic materials through the self-assembly of multi-domain peptides and proteins over the past decade have been realized. Such engineered systems have wide-ranging application in bioengineering and medicine. This review focuses on fundamental fiber forming α-helical coiled-coil peptides, peptide amphiphiles, and amyloid-based self-assembling peptides; followed by higher order collagen- and elastin-mimetic peptides with an emphasis on chemical / biological characterization and biomimicry. PMID:27022140

Self-assembly of active amphiphilic Janus particles

Science.gov (United States)

Mallory, S. A.; Alarcon, F.; Cacciuto, A.; Valeriani, C.

2017-12-01

In this article, we study the phenomenology of a two dimensional dilute suspension of active amphiphilic Janus particles. We analyze how the morphology of the aggregates emerging from their self-assembly depends on the strength and the direction of the active forces. We systematically explore and contrast the phenomenologies resulting from particles with a range of attractive patch coverages. Finally, we illustrate how the geometry of the colloids and the directionality of their interactions can be used to control the physical properties of the assembled active aggregates and suggest possible strategies to exploit self-propulsion as a tunable driving force for self-assembly.

Glucose-Neopentyl Glycol (GNG) Amphiphiles for Membrane Protein Solubilization, Stabilization and Crystallization

OpenAIRE

Chae, Pil Seok; Rana, Rohini R.; Gotfryd, Kamil; Rasmussen, Søren G. F.; Kruse, Andrew C.; Cho, Kyung Ho; Capaldi, Stefano; Carlsson, Emil; Kobilka, Brian; Loland, Claus J.; Gether, Ulrik; Banerjee, Surajit; Byrne, Bernadette; Lee, John K.; Gellman, Samuel H.

2013-01-01

The development of a new class of surfactants for membrane protein manipulation, “GNG amphiphiles”, is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo et al.

Replication of simulated prebiotic amphiphile vesicles controlled by experimental lipid physicochemical properties

International Nuclear Information System (INIS)

Armstrong, Don L; Zidovetzki, Raphael; Markovitch, Omer; Lancet, Doron

2011-01-01

We present a new embodiment of the graded autocatalysis replication domain (GARD) for the growth, replication and evolution of lipid vesicles based on a semi-empirical foundation using experimentally measured kinetic values of selected extant lipid species. Extensive simulations using this formalism elucidated the details of the dependence of the replication and properties of the vesicles on the physicochemical properties and concentrations of the lipids, both in the environment and in the vesicle. As expected, the overall concentration and number of amphiphilic components strongly affect average replication time. Furthermore, variations in acyl chain length and unsaturation of vesicles also influence replication rate, as do the relative concentrations of individual lipid types. Understanding of the dependence of replication rates on physicochemical parameters opens a new direction in the study of prebiotic vesicles and lays the groundwork for future studies involving the competition between lipid vesicles for available amphiphilic monomers

Solvent polarity effects on supramolecular chirality of a polyfluorene-thiophene copolymer.

Science.gov (United States)

Hirahara, Takashi; Yoshizawa-Fujita, Masahiro; Takeoka, Yuko; Rikukawa, Masahiro

2018-06-01

This study demonstrates the supramolecular chirality control of a conjugated polymer via solvent polarity. We designed and synthesized a chiral polyfluorene-thiophene copolymer having two different chiral side chains at the 9-position of the fluorene unit. Chiral cyclic and alkyl ethers with different polarities were selected as the chiral side chains. The sign of the circular dichroism spectra in the visible wavelength region was affected by the solvent system, resulting from the change of supramolecular structure. The estimation of the solubility parameter revealed that the solubility difference of the side chains contributed to the change of the circular dichroism sign, which was also observed in spin-coated films prepared from good solvents having different polarities. © 2018 Wiley Periodicals, Inc.

Predicting supramolecular self-assembly on reconstructed metal surfaces

Science.gov (United States)

Roussel, Thomas J.; Barrena, Esther; Ocal, Carmen; Faraudo, Jordi

2014-06-01

The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule-molecule interactions are enhanced in a way that long-range order is promoted. Also, the presence of a distortion in a reconstructed surface pattern not only induces the presence of long-range order but also is able to drive the organization of DIP into two coexisting homochiral domains, in quantitative agreement with STM experiments. On the other hand, only short range order is obtained in other reconstructions of the Au(111) surface. The simulation strategy opens interesting perspectives to tune the supramolecular structure by simulation design and surface engineering if choosing the right molecular building blocks and stabilising the chosen reconstruction pattern.The prediction of supramolecular self-assembly onto solid surfaces is still challenging in many situations of interest for nanoscience. In particular, no previous simulation approach has been capable to simulate large self-assembly patterns of organic molecules over reconstructed surfaces (which have periodicities over large distances) due to the large number of surface atoms and adsorbing molecules involved. Using a novel simulation technique, we report here large scale simulations of the self-assembly patterns of an organic molecule (DIP) over different reconstructions of the Au(111) surface. We show that on particular reconstructions, the molecule

Hierarchical self-assembly of a bow-shaped molecule bearing self-complementary hydrogen bonding sites into extended supramolecular assemblies.

Science.gov (United States)

Ikeda, Masato; Nobori, Tadahito; Schmutz, Marc; Lehn, Jean-Marie

2005-01-07

The bow-shaped molecule 1 bearing a self-complementary DAAD-ADDA (D=donor A=acceptor) hydrogen-bonding array generates, in hydrocarbon solvents, highly ordered supramolecular sheet aggregates that subsequently give rise to gels by formation of an entangled network. The process of hierarchical self-assembly of compound 1 was investigated by the concentration and temperature dependence of UV-visible and (1)H NMR spectra, fluorescence spectra, and electron microscopy data. The temperature dependence of the UV-visible spectra indicates a highly cooperative process for the self-assembly of compound 1 in decaline. The electron micrograph of the decaline solution of compound 1 (1.0 mM) revealed supramolecular sheet aggregates forming an entangled network. The selected area electronic diffraction patterns of the supramolecular sheet aggregates were typical for single crystals, indicative of a highly ordered assembly. The results exemplify the generation, by hierarchical self-assembly, of highly organized supramolecular materials presenting novel collective properties at each level of organization.

An approach to the construction of tailor-made amphiphilic peptides that strongly and selectively bind to hairpin RNA targets.

Science.gov (United States)

Lee, Su Jin; Hyun, Soonsil; Kieft, Jeffrey S; Yu, Jaehoon

2009-02-18

The hairpin RNA motif is one of the most frequently observed secondary structures and is often targeted by therapeutic agents. An amphiphilic peptide with seven lysine and eight leucine residues and its derivatives were designed for use as ligands against RNA hairpin motifs. We hypothesized that variations in both the hydrophobic leucine-rich and hydrophilic lysine-rich spheres of these amphiphilic peptides would create extra attractive interactions with hairpin RNA targets. A series of alanine-scanned peptides were probed to identify the most influential lysine residues in the hydrophilic sphere. The binding affinities of these modified peptides with several hairpins, such as RRE, TAR from HIV, a short hairpin from IRES of HCV, and a hairpin from the 16S A-site stem from rRNA, were determined. Since the hairpin from IRES of HCV was the most susceptible to the initial series of alanine-scanned peptides, studies investigating how further variations in the peptides effect binding employed the IRES hairpin. Next, the important Lys residues were substituted by shorter chain amines, such as ornithine, to place the peptide deeper into the hairpin groove. In a few cases, a 70-fold improved binding was observed for peptides that contained the specifically located shorter amine side chains. To further explore changes in binding affinities brought about by alterations in the hydrophobic sphere, tryptophan residues were introduced in place of leucine. A few peptides with tryptophan in specific positions also displayed 70-fold improved binding affinities. Finally, double mutant peptides incorporating both specifically located shorter amine side chains in the hydrophilic region and tryptophan residues in the hydrophobic region were synthesized. The binding affinities of peptides containing the simple double modification were observed to be 80 times lower, and their binding specificities were increased 40-fold. The results of this effort provide important information about

Supramolecular assembly of organic bicapped Keggin polyoxometalate

International Nuclear Information System (INIS)

Han Zhangang; Zhao Yulong; Peng Jun; Ma Huiyuan; Liu Qun; Wang Enbo; Hu Ninghai

2004-01-01

Two novel supramolecular assemblies of organic bicapped Keggin polyoxometalates (pbpy) 8 H 3 [PW 12 O 40 ]·2H 2 O (1) and (pbpy) 4 H[PMo 12 O 40 (VO)] (2) (pbpy=5-phenyl-2-(4-pyridinyl)pyridine) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Crystallographic data for compound (1), C 128 H 103 N 16 O 42 PW 12 , triclinic, space group P1-bar: a=13.4759(8) A, b=14.6395(11) A, c=16.5743(10) A, α=95.764(2) deg., β=102.166(2) deg., γ=92.9870(10) deg., Z=1, V=3171.1(4) A 3 ; for compound (2), C 64 H 49 N 8 O 41 PMo 12 V, triclinic, space group P1-bar: a=11.5377(11) A, b=12.7552(8) A, c=14.9599(10) A, α=72.270(4) deg., β=88.916(2) deg., γ=67.865(4) deg., Z=1, V=1931.0(3) A 3 . X-ray analyses show that both 1 and 2 represent rare organic bicapped Keggin structures and are supported by supramolecular interactions to extend into a 3D framework. In particular, the unusual structure feature of compound 2 contains a simultaneously organic and inorganic capped structure

Glucose-Neopentyl Glycol (GNG) Amphiphiles for Membrane Protein Solubilization, Stabilization and Crystallization

Science.gov (United States)

Rana, Rohini R.; Gotfryd, Kamil; Rasmussen, Søren G. F.; Kruse, Andrew C.; Cho, Kyung Ho; Capaldi, Stefano; Carlsson, Emil; Kobilka, Brian; Loland, Claus J.; Gether, Ulrik; Banerjee, Surajit

2012-01-01

The development of a new class of surfactants for membrane protein manipulation, “GNG amphiphiles”, is reported. These amphiphiles display promising behavior for membrane proteins, as demonstrated recently by the high resolution structure of a sodium-pumping pyrophosphatase reported by Kellosalo et al. PMID:23165475

Supramolecular Architectures and Mimics of Complex Natural Folds Derived from Rationally Designed alpha-Helical Protein Structures

Science.gov (United States)

Tavenor, Nathan Albert

Protein-based supramolecular polymers (SMPs) are a class of biomaterials which draw inspiration from and expand upon the many examples of complex protein quaternary structures observed in nature: collagen, microtubules, viral capsids, etc. Designing synthetic supramolecular protein scaffolds both increases our understanding of natural superstructures and allows for the creation of novel materials. Similar to small-molecule SMPs, protein-based SMPs form due to self-assembly driven by intermolecular interactions between monomers, and monomer structure determines the properties of the overall material. Using protein-based monomers takes advantage of the self-assembly and highly specific molecular recognition properties encodable in polypeptide sequences to rationally design SMP architectures. The central hypothesis underlying our work is that alpha-helical coiled coils, a well-studied protein quaternary folding motif, are well-suited to SMP design through the addition of synthetic linkers at solvent-exposed sites. Through small changes in the structures of the cross-links and/or peptide sequence, we have been able to control both the nanoscale organization and the macroscopic properties of the SMPs. Changes to the linker and hydrophobic core of the peptide can be used to control polymer rigidity, stability, and dimensionality. The gaps in knowledge that this thesis sought to fill on this project were 1) the relationship between the molecular structure of the cross-linked polypeptides and the macroscopic properties of the SMPs and 2) a means of creating materials exhibiting multi-dimensional net or framework topologies. Separate from the above efforts on supramolecular architectures was work on improving backbone modification strategies for an alpha-helix in the context of a complex protein tertiary fold. Earlier work in our lab had successfully incorporated unnatural building blocks into every major secondary structure (beta-sheet, alpha-helix, loops and beta

Autoamplification of molecular chirality through the induction of supramolecular chirality

NARCIS (Netherlands)

van Dijken, Derk Jan; Beierle, John M.; Stuart, Marc C. A.; Szymanski, Wiktor; Browne, Wesley R.; Feringa, Ben L.

2014-01-01

The novel concept for the autoamplification of molecular chirality, wherein the amplification proceeds through the induction of supramolecular chirality, is presented. A solution of prochiral, ring-open diarylethenes is doped with a small amount of their chiral, ring-closed counterpart. The

Theory of the Flower Micelle Formation of Amphiphilic Random and Periodic Copolymers in Solution

Directory of Open Access Journals (Sweden)

Takahiro Sato

2018-01-01

Full Text Available The mixing Gibbs energy Δgm for the flower-micelle phase of amphiphilic random and periodic (including alternating copolymers was formulated on the basis of the lattice model. The formulated Δgm predicts (1 the inverse proportionality of the aggregation number to the degree of polymerization of the copolymer, (2 the increase of the critical micelle concentration with decreasing the hydrophobe content, and (3 the crossover from the micellization to the liquid–liquid phase separation as the hydrophobe content increases. The transition from the uni-core flower micelle to the multi-core flower necklace as the degree of polymerization increases was also implicitly indicated by the theory. These theoretical results were compared with experimental results for amphiphilic random and alternating copolymers reported so far.

Synthesis and Application of a New Amphiphilic Antioxidant.

Science.gov (United States)

Soliman, Hanaa M; Arafat, Shaker M; Basuny, Amany M; Shattory, Y El-

2017-11-01

A new amphiphilic antioxidant (tannyl stearate) derived from reaction of tannic acid with stearic acid was synthesized in order to improve tannic acid solubility in lipid materials. This reaction gives many products having different degree of esterification (tannyl mono, di, tri, tetra, penta, hexa, hepta……stearate) which were separated using silica gel column chromatography and tentative identification was carried out using thin layer chromatography (TLC). The intrinsic viscosities (η) were used to differentiate between the different molecular weight of the produced esters 1) . Tannyl penta stearate is assumed to be the most suitable amphiphilic antioxidant derivative, where those derivatives with less degree of esterification would be less soluble in fat, and those of higher degree of esterification would exhaust more hydroxyl group that cause decreases of antioxidant activity. The structure of tannyl penta stearate was approved depending on its chemical analysis and spectral data (IR, H 1 NMR,). The emulsification power of tannyl penta stearate was then determined according to method described by El-Sukkary et al. 2) , in order to prove its amphiphilic property. Then tannyl penta stearate was tested for its antioxidant and radical scavenging activities in three different manners, those are, lipid oxidation in sunflower oil using Rancimat, (DPPH) free radical scavenging and total antioxidant activity. {Pure tannic acid (T), butylhydroxyanisol (BHA) and butylhydroxytoluene (BHT) were used as reference antioxidant radical saving compounds}. Then tannyl penta stearate was added to sunflower oil, frying process was carried out and all physicochemical parameters of the oil were considered, and compared to other reference antioxidant in order to study the effect of this new antioxidant toward oil stability. Acute oral toxicity of the tannyl penta stearate was carried out using albino mice of 21-25 g body weight to determine its safety according to the method

Supramolecular curcumin-barium prodrugs for formulating with ceramic particles.

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Kamalasanan, Kaladhar; Anupriya; Deepa, M K; Sharma, Chandra P

2014-10-01

A simple and stable curcumin-ceramic combined formulation was developed with an aim to improve curcumin stability and release profile in the presence of reactive ceramic particles for potential dental and orthopedic applications. For that, curcumin was complexed with barium (Ba(2+)) to prepare curcumin-barium (BaCur) complex. Upon removal of the unbound curcumin and Ba(2+) by dialysis, a water-soluble BaCur complex was obtained. The complex was showing [M+1](+) peak at 10,000-20,000 with multiple fractionation peaks of MALDI-TOF-MS studies, showed that the complex was a supramolecular multimer. The (1)H NMR and FTIR studies revealed that, divalent Ba(2+) interacted predominantly through di-phenolic groups of curcumin to form an end-to-end complex resulted in supramolecular multimer. The overall crystallinity of the BaCur was lower than curcumin as per XRD analysis. The complexation of Ba(2+) to curcumin did not degrade curcumin as per HPLC studies. The fluorescence spectrum was blue shifted upon Ba(2+) complexation with curcumin. Monodisperse nanoparticles with size less than 200dnm was formed, out of the supramolecular complex upon dialysis, as per DLS, and upon loading into pluronic micelles the size was remaining in similar order of magnitude as per DLS and AFM studies. Stability of the curcumin was improved greater than 50% after complexation with Ba(2+) as per UV/Vis spectroscopy. Loading of the supramloecular nanoparticles into pluronic micelles had further improved the stability of curcumin to approx. 70% in water. These BaCur supramolecule nanoparticles can be considered as a new class of prodrugs with improved solubility and stability. Subsequently, ceramic nanoparticles with varying chemical composition were prepared for changing the material surface reactivity in terms of the increase in, degradability, surface pH and protein adsorption. Further, these ceramic particles were combined with curcumin prodrug formulations and optimized the curcumin release

Programming supramolecular biohybrids as precision therapeutics.

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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

Differences in Cellulosic Supramolecular Structure of Compositionally Similar Rice Straw Affect Biomass Metabolism by Paddy Soil Microbiota.

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Tatsuki Ogura

Full Text Available Because they are strong and stable, lignocellulosic supramolecular structures in plant cell walls are resistant to decomposition. However, they can be degraded and recycled by soil microbiota. Little is known about the biomass degradation profiles of complex microbiota based on differences in cellulosic supramolecular structures without compositional variations. Here, we characterized and evaluated the cellulosic supramolecular structures and composition of rice straw biomass processed under different milling conditions. We used a range of techniques including solid- and solution-state nuclear magnetic resonance (NMR and Fourier transform infrared spectroscopy followed by thermodynamic and microbial degradability characterization using thermogravimetric analysis, solution-state NMR, and denaturing gradient gel electrophoresis. These measured data were further analyzed using an "ECOMICS" web-based toolkit. From the results, we found that physical pretreatment of rice straw alters the lignocellulosic supramolecular structure by cleaving significant molecular lignocellulose bonds. The transformation from crystalline to amorphous cellulose shifted the thermal degradation profiles to lower temperatures. In addition, pretreated rice straw samples developed different microbiota profiles with different metabolic dynamics during the biomass degradation process. This is the first report to comprehensively characterize the structure, composition, and thermal degradation and microbiota profiles using the ECOMICS toolkit. By revealing differences between lignocellulosic supramolecular structures of biomass processed under different milling conditions, our analysis revealed how the characteristic compositions of microbiota profiles develop in addition to their metabolic profiles and dynamics during biomass degradation.

Role of nano-range amphiphilic polymers in seed quality enhancement of soybean and imidacloprid retention capacity on seed coatings.

Science.gov (United States)

Adak, Totan; Kumar, Jitendra; Shakil, Najam A; Pandey, Sushil

2016-10-01

Nano-size and wide-range solubility of amphiphilic polymers (having both hydrophilic and hydrophobic blocks) can improve uniformity in seed coatings. An investigation was carried out to assess the positive effect of amphiphilic polymers over hydrophilic or hydrophobic polymers as seed coating agents and pesticide carriers. Amphiphilic polymers with 127.5-354 nm micelle size were synthesized in the laboratory using polyethylene glycols and aliphatic di-acids. After 6 months of storage, germination of uncoated soybean seeds decreased drastically from 97.80 to 81.55%, while polymer-coated seeds showed 89.44-95.92% germination. Similarly, vigour index-1 was reduced from 3841.10 to 2813.06 for control seeds but ranged from 3375.59 to 3844.60 for polymer-coated seeds after 6 months. The developed imidacloprid formulations retained more pesticide on soybean seed coatings than did a commercial formulation (Gaucho(®) 600 FS). The time taken for 50% release of imidacloprid from seed coatings in water was 7.12-9.11 h for the developed formulations and 0.41 h for the commercial formulation. Nano-range amphiphilic polymers can be used to protect soybean seeds from ageing. Formulations as seed treatments may produce improved and sustained efficacy with minimum environmental contamination. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Synthesis and crystal structure of a wheel-shaped supramolecular ...

Indian Academy of Sciences (India)

41-218/2012 (SR)), India for financial support. DG and BS thank the Council of Scientific and Indus- trial Research (CSIR) for Senior Research Fellowship. We are grateful to Perkin-Elmer for ESI-Mass analysis. References. 1. (a) Lehn J M 1995 In Supramolecular Chem- istry, Concepts and Perspectives (Weinheim: VCH);.

Preparation and Microbiological Evaluation of Amphiphilic Kanamycin-Lipoamino Acid Ion-Pairs

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Rosario Pignatello

2014-05-01

Full Text Available Amphiphilic ion-pairs of kanamycin (KAN were prepared by evaporation of a water-ethanol co-solution of KAN base and a lipoamino acid bearing a 12-carbon atoms alkyl side chain (LAA12, at different molar ratios. Infrared spectroscopy confirmed the structure of ion-pairs, while differential scanning calorimetry (DSC and powder X-ray diffractometry (PXRD studies supported the formation of new saline species with a different crystalline structure than the starting components. The solubility pattern shown in a range of both aqueous and organic solvents confirmed that the ion-pairs possess an amphiphilic character. The LAA12 counter-ion showed not to improve the antibacterial activity of KAN, suggesting that such chemical strategy is not able to favor the penetration of this drug inside the bacteria cells. Nevertheless, a slight improving, i.e., a one-fold dilution, was observed in E. coli. The present study can also serve as the basis for a further evaluation of LAA ion-pairing of antibiotics, as a means to improve the loading of hydrophilic drugs into lipid-based nanocarriers.

Aminoglycoside-derived amphiphilic nanoparticles for molecular delivery.

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Miryala, Bhavani; Godeshala, Sudhakar; Grandhi, Taraka Sai Pavan; Christensen, Matthew D; Tian, Yanqing; Rege, Kaushal

2016-10-01

The development of effective drug carriers can lead to improved outcomes in a variety of disease conditions. Aminoglycosides have been used as antibacterial therapeutics, and are attractive as monomers for the development of polymeric materials in various applications. Here, we describe the development of novel aminoglycoside-derived amphiphilic nanoparticles for drug delivery, with an eye towards ablation of cancer cells. The aminoglycoside paromomycin was first cross-linked with resorcinol diglycidyl ether leading to the formation of a poly (amino ether), PAE. PAE molecules were further derivatized with methoxy-terminated poly(ethylene glycol) or mPEG resulting in the formation of mPEG-PAE polymer, which self-assembled to form nanoparticles. Formation of the mPEG-PAE amphiphile was characterized using (1)H NMR, (13)C NMR, gel permeation chromatography (GPC) and FTIR spectroscopy. Self-assembly of the polymer into nanoparticles was characterized using dynamic light scattering, zeta potential analyses, atomic force microscopy (AFM) and the pyrene fluorescence assay. mPEG-PAE nanoparticles were able to carry significant amounts of doxorubicin (DOX), presumably by means of hydrophobic interactions between the drug and the core. Cell-based studies indicated that mPEG-PAE nanoparticles, loaded with doxorubicin, were able to induce significant loss in viabilities of PC3 human prostate cancer, MDA-MB-231 human breast cancer, and MB49 murine bladder cancer cells; empty nanoparticles resulted in negligible losses of cell viability under the conditions investigated. Taken together, our results indicate that the mPEG-PAE nanoparticle platform is attractive for drug delivery in different applications, including cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis, spectroscopy, thermal studies and supramolecular ...

Indian Academy of Sciences (India)

TECS

Synthesis, spectroscopy, thermal studies and supramolecular structures of two .... J = 9 Hz), 8∙13 (d, 2H, J = 9 Hz), 7∙69 (s, 1H), 7∙04. (s, 2H). ... 1H NMR (D2O): δ (in ppm); 8∙05 (d, 2H, ..... 86∙33 (2). 86∙92(1). 87∙08(2). V (Ε3). 553∙1(6). 573∙71(5). 561∙56(14). 557∙5(3) .... Mn, Co and Ni complexes.28–30 The observed inter-.

Supramolecular effects as driving force of dipyrrin based functional materials engineering

Science.gov (United States)

Banakova, E.; Bobrov, A.; Kazak, A.; Marfin, Yu; Merkushev, D.; Molchanov, E.; Rumyantsev, E.; Shipalova, M.; Usoltsev, S.; Vodyanova, O.

2018-01-01

Dipyrrin based luminophores are of major interest in different areas of chemistry, material science and molecular biology. Vast variety of the structures with dipyrrin motif were synthesized and investigated up to date. Modern trend in the dipyrrin chemistry is the aimed functionalization of the ligand or complex structure allowing to gain the mechanism based on supramolecular interactions for controlling spectral and photophysical characteristics of compounds for tuning practically valuable properties for specific tasks. Presented paper summarize the results of our research group, working in the field of dipyrrin complexes with p-elements: synthesis, spectral characteristics evaluation and possibilities of practical application investigation. Discussion is focused on the opportunities of molecules preorganization for achieving the supramolecular interactions causing the tuning of fluorescence of the compounds in solutions, polymeric matrices and thin films.

Solvent Clathrate Driven Dynamic Stereomutation of a Supramolecular Polymer with Molecular Pockets.

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Kulkarni, Chidambar; Korevaar, Peter A; Bejagam, Karteek K; Palmans, Anja R A; Meijer, E W; George, Subi J

2017-10-04

Control over the helical organization of synthetic supramolecular systems is intensively pursued to manifest chirality in a wide range of applications ranging from electron spin filters to artificial enzymes. Typically, switching the helicity of supramolecular assemblies involves external stimuli or kinetic traps. However, efforts to achieve helix reversal under thermodynamic control and to understand the phenomena at a molecular level are scarce. Here we present a unique example of helix reversal (stereomutation) under thermodynamic control in the self-assembly of a coronene bisimide that has a 3,5-dialkoxy substitution on the imide phenyl groups (CBI-35CH), leading to "molecular pockets" in the assembly. The stereomutation was observed only if the CBI monomer possesses molecular pockets. Detailed chiroptical studies performed in alkane solvents with different molecular structures reveal that solvent molecules intercalate or form clathrates within the molecular pockets of CBI-35CH at low temperature (263 K), thereby triggering the stereomutation. The interplay among the helical assembly, molecular pockets, and solvent molecules is further unraveled by explicit solvent molecular dynamics simulations. Our results demonstrate how the molecular design of self-assembling building blocks can orchestrate the organization of surrounding solvent molecules, which in turn dictates the helical organization of the resulting supramolecular assembly.

Thermoresponsive Supramolecular Chemotherapy by "V"-Shaped Armed β-Cyclodextrin Star Polymer to Overcome Drug Resistance.

Science.gov (United States)

Fan, Xiaoshan; Cheng, Hongwei; Wang, Xiaoyuan; Ye, Enyi; Loh, Xian Jun; Wu, Yun-Long; Li, Zibiao

2018-04-01

Pump mediated drug efflux is the key reason to result in the failure of chemotherapy. Herein, a novel star polymer β-CD-v-(PEG-β-PNIPAAm) 7 consisting of a β-CD core, grafted with thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) and biocompatible poly(ethylene glycol) (PEG) in the multiple "V"-shaped arms is designed and further fabricated into supramolecular nanocarriers for drug resistant cancer therapy. The star polymer could encapsulate chemotherapeutics between β-cyclodextrin and anti-cancer drug via inclusion complex (IC). Furthermore, the temperature induced chain association of PNIPAAm segments facilitated the IC to form supramolecular nanoparticles at 37 °C, whereas the presence of PEG impart great stability to the self-assemblies. When incubated with MDR-1 membrane pump regulated drug resistant tumor cells, much higher and faster cellular uptake of the supramolecular nanoparticles were detected, and the enhanced intracellular retention of drugs could lead to significant inhibition of cell growth. Further in vivo evaluation showed high therapeutic efficacy in suppressing drug resistant tumor growth without a significant impact on the normal functions of main organs. This work signifies thermo-responsive supramolecular chemotherapy is promising in combating pump mediated drug resistance in both in vitro and in vivo models, which may be encouraging for the advanced drug delivery platform design to overcome drug resistant cancer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monoolein lipid phases as incorporation and enrichment materials for membrane protein crystallization.

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Ellen Wallace

Full Text Available The crystallization of membrane proteins in amphiphile-rich materials such as lipidic cubic phases is an established methodology in many structural biology laboratories. The standard procedure employed with this methodology requires the generation of a highly viscous lipidic material by mixing lipid, for instance monoolein, with a solution of the detergent solubilized membrane protein. This preparation is often carried out with specialized mixing tools that allow handling of the highly viscous materials while minimizing dead volume to save precious membrane protein sample. The processes that occur during the initial mixing of the lipid with the membrane protein are not well understood. Here we show that the formation of the lipidic phases and the incorporation of the membrane protein into such materials can be separated experimentally. Specifically, we have investigated the effect of different initial monoolein-based lipid phase states on the crystallization behavior of the colored photosynthetic reaction center from Rhodobacter sphaeroides. We find that the detergent solubilized photosynthetic reaction center spontaneously inserts into and concentrates in the lipid matrix without any mixing, and that the initial lipid material phase state is irrelevant for productive crystallization. A substantial in-situ enrichment of the membrane protein to concentration levels that are otherwise unobtainable occurs in a thin layer on the surface of the lipidic material. These results have important practical applications and hence we suggest a simplified protocol for membrane protein crystallization within amphiphile rich materials, eliminating any specialized mixing tools to prepare crystallization experiments within lipidic cubic phases. Furthermore, by virtue of sampling a membrane protein concentration gradient within a single crystallization experiment, this crystallization technique is more robust and increases the efficiency of identifying productive

From superamphiphobic to amphiphilic polymeric surfaces with ordered hierarchical roughness fabricated with colloidal lithography and plasma nanotexturing.

Science.gov (United States)

Ellinas, K; Tserepi, A; Gogolides, E

2011-04-05

Ordered, hierarchical (triple-scale), superhydrophobic, oleophobic, superoleophobic, and amphiphilic surfaces on poly(methyl methacrylate) PMMA polymer substrates are fabricated using polystyrene (PS) microparticle colloidal lithography, followed by oxygen plasma etching-nanotexturing (for amphiphilic surfaces) and optional subsequent fluorocarbon plasma deposition (for amphiphobic surfaces). The PS colloidal microparticles were assembled by spin-coating. After etching/nanotexturing, the PMMA plates are amphiphilic and exhibit hierarchical (triple-scale) roughness with microscale ordered columns, and dual-scale (hundred nano/ten nano meter) nanoscale texture on the particles (top of the column) and on the etched PMMA surface. The spacing, diameter, height, and reentrant profile of the microcolumns are controlled with the etching process. Following the design requirements for superamphiphobic surfaces, we demonstrate enhancement of both hydrophobicity and oleophobicity as a result of hierarchical (triple-scale) and re-entrant topography. After fluorocarbon film deposition, we demonstrate superhydrophobic surfaces (contact angle for water 168°, compared to 110° for a flat surface), as well as superoleophobic surfaces (153° for diiodomethane, compared to 80° for a flat surface).

A Review of the Role of Amphiphiles in Biomass to Ethanol Conversion

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William Gibbons

2013-04-01

Full Text Available One of the concerns for economical production of ethanol from biomass is the large volume and high cost of the cellulolytic enzymes used to convert biomass into fermentable sugars. The presence of acetyl groups in hemicellulose and lignin in plant cell walls reduces accessibility of biomass to the enzymes and makes conversion a slow process. In addition to low enzyme accessibility, a rapid deactivation of cellulases during biomass hydrolysis can be another factor contributing to the low sugar recovery. As of now, the economical reduction in lignin content of the biomass is considered a bottleneck, and raises issues for several reasons. The presence of lignin in biomass reduces the swelling of cellulose fibrils and accessibility of enzyme to carbohydrate polymers. It also causes an irreversible adsorption of the cellulolytic enzymes that prevents effective enzyme activity and recycling. Amphiphiles, such as surfactants and proteins have been found to improve enzyme activity by several mechanisms of action that are not yet fully understood. Reduction in irreversible adsorption of enzyme to non-specific sites, reduction in viscosity of liquid and surface tension and consequently reduced contact of enzyme with air-liquid interface, and modifications in biomass chemical structure are some of the benefits derived from surface active molecules. Application of some of these amphiphiles could potentially reduce the capital and operating costs of bioethanol production by reducing fermentation time and the amount of enzyme used for saccharification of biomass. In this review article, the benefit of applying amphiphiles at various stages of ethanol production (i.e., pretreatment, hydrolysis and hydrolysis-fermentation is reviewed and the proposed mechanisms of actions are described.

Tetrazole amphiphile inducing growth of conducting polymers hierarchical nanostructures and their electromagnetic absorption properties

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Xie, Aming; Sun, Mengxiao; Zhang, Kun; Xia, Yilu; Wu, Fan

2018-05-01

Conducting polymers (CPs) at nano scales endow materials with special optical, electrical, and magnetic properties. The crucial factor to construct and regulate the micro-structures of CPs is the inducing reagent, particular in its chemical structure, such active sites, self-assembling properties. In this paper, we design and synthesize an amphiphile bearing tetrazole moiety on its skeleton, and use this amphiphile as an inducing reagent to prepare and regulate the micro-structures of a series of CPs including polypyrrole, polyaniline, poly(3,4-ethylenedioxythiophene) and poly(p-phenylenediamine). Because of the unique electric properties of CPs and size effect, we next explored the electromagnetic absorption performances of these CPs nanostructures. A synergetic combination of electric loss and magnetic loss is used to explain the absorption mechanism of these CPs nano-structures.

Synthesis of an amphiphilic dendrimer-like block copolymer and its application on drug delivery

KAUST Repository

Wang, Shuaipeng

2014-10-27

Dendrimer-like amphiphilic copolymer is a kind of three-dimensional spherical structure polymer. An amphiphilic dendrimer-like diblock copolymer, PEEGE-G2-b-PEO(OH)12, constituted of a hydrophobic poly(ethoxyethyl glycidol ether) inner core and a hydrophilic poly(ethylene oxide) outer layer, has been successfully synthesized by the living anionic ring-opening polymerization method. The intermediates and targeted products were characterized with 1H NMR spectroscopy and gel permeation chromatography. The application on drug delivery of dendrimer-like diblock copolymer PEEGE-G2-b-PEO(OH)12 using DOX as a model drug was also studied. The drug loading content and encapsulation efficiency were found at 13.07% and 45.75%, respectively. In vitro release experiment results indicated that the drug-loaded micelles exhibited a sustained release behavior under acidic media.

Acid-Labile Amphiphilic PEO-b-PPO-b-PEO Copolymers: Degradable Poloxamer Analogs.

Science.gov (United States)

Worm, Matthias; Kang, Biao; Dingels, Carsten; Wurm, Frederik R; Frey, Holger

2016-05-01

Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions (Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation "on demand." © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New amphiphilic glycopolypeptide conjugate capable of self-assembly in water into reduction-sensitive micelles for triggered drug release

Energy Technology Data Exchange (ETDEWEB)

Yang, Hui-Kang [DSAPM Lab and PCFM Lab, Department of Polymer and Materials Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Zhang, Li-Ming, E-mail: ceszhlm@mail.sysu.edu.cn [DSAPM Lab and PCFM Lab, Department of Polymer and Materials Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Guangdong Provincial Key Laboratory of New Drug Design and Evaluation, School of Pharmaceutical Science, Sun Yat-sen University, Guangzhou 510006 (China)

2014-08-01

For the development of biomimetic carriers for stimuli-sensitive delivery of anticancer drugs, a novel amphiphilic glycopolypeptide conjugate containing the disulfide bond was prepared for the first time by the ring-opening polymerization of benzyl glutamate N-carboxy anhydride in the presence of (propargyl carbamate)ethyl dithio ethylamine and then click conjugation with α-azido dextran. Its structure was characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance analyses. Owing to its amphiphilic nature, such a conjugate could self assemble into nanosize micelles in aqueous medium, as confirmed by fluorometry, transmission electron microscopy and dynamic light scattering. For the resultant micelles, it was found to encapsulate poorly water-soluble anticancer drug (methotrexate, MTX) with the loading efficiency of 45.2%. By the in vitro drug release tests, the release rate of encapsulated MTX was observed to be accelerated significantly in the presence of 10 mM 1,4-dithio-DL-threitol (DTT), analogous to the intracellular redox potential. - Graphical abstract: New amphiphilic glycopolypeptide conjugate containing the disulfide bond could self-assemble in aqueous solution into reduction-sensitive micelles for triggered release of an anticancer drug (methotrexate, MTX) in the presence of 10 mM 1,4-dithio-DL-threitol (DTT). - Highlights: • Amphiphilic glycopolypeptide conjugate containing disulfide bond was prepared. • Such a conjugate self assembled in aqueous solution into nanosize micelles. • The resultant micelles could encapsulate effectively methotrexate drug. • The drug-loaded micelles showed a reduction-sensitive drug release behavior.

New amphiphilic glycopolypeptide conjugate capable of self-assembly in water into reduction-sensitive micelles for triggered drug release

International Nuclear Information System (INIS)

Yang, Hui-Kang; Zhang, Li-Ming

2014-01-01

For the development of biomimetic carriers for stimuli-sensitive delivery of anticancer drugs, a novel amphiphilic glycopolypeptide conjugate containing the disulfide bond was prepared for the first time by the ring-opening polymerization of benzyl glutamate N-carboxy anhydride in the presence of (propargyl carbamate)ethyl dithio ethylamine and then click conjugation with α-azido dextran. Its structure was characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance analyses. Owing to its amphiphilic nature, such a conjugate could self assemble into nanosize micelles in aqueous medium, as confirmed by fluorometry, transmission electron microscopy and dynamic light scattering. For the resultant micelles, it was found to encapsulate poorly water-soluble anticancer drug (methotrexate, MTX) with the loading efficiency of 45.2%. By the in vitro drug release tests, the release rate of encapsulated MTX was observed to be accelerated significantly in the presence of 10 mM 1,4-dithio-DL-threitol (DTT), analogous to the intracellular redox potential. - Graphical abstract: New amphiphilic glycopolypeptide conjugate containing the disulfide bond could self-assemble in aqueous solution into reduction-sensitive micelles for triggered release of an anticancer drug (methotrexate, MTX) in the presence of 10 mM 1,4-dithio-DL-threitol (DTT). - Highlights: • Amphiphilic glycopolypeptide conjugate containing disulfide bond was prepared. • Such a conjugate self assembled in aqueous solution into nanosize micelles. • The resultant micelles could encapsulate effectively methotrexate drug. • The drug-loaded micelles showed a reduction-sensitive drug release behavior

From steroids to aqueous supramolecular chemistry: an autobiographical career review.

Science.gov (United States)

Gibb, Bruce C

2016-01-01

The focus of my group's research is aqueous supramolecular chemistry; we try to understand how chemical entities interact with water and consequently how they interact with each other. This personal history recounts my career experiences that led to his involvement with this fascinating area of science.

Supramolecular Complexation of Carbohydrates for the Bioavailability Enhancement of Poorly Soluble Drugs.

Science.gov (United States)

Cho, Eunae; Jung, Seunho

2015-10-27

In this review, a comprehensive overview of advances in the supramolecular complexes of carbohydrates and poorly soluble drugs is presented. Through the complexation process, poorly soluble drugs could be efficiently delivered to their desired destinations. Carbohydrates, the most abundant biomolecules, have diverse physicochemical properties owing to their inherent three-dimensional structures, hydrogen bonding, and molecular recognition abilities. In this regard, oligosaccharides and their derivatives have been utilized for the bioavailability enhancement of hydrophobic drugs via increasing the solubility or stability. By extension, polysaccharides and their derivatives can form self-assembled architectures with poorly soluble drugs and have shown increased bioavailability in terms of the sustained or controlled drug release. These supramolecular systems using carbohydrate will be developed consistently in the field of pharmaceutical and medical application.

A supramolecular miktoarm star polymer based on porphyrin metal complexation in water.

Science.gov (United States)

Hou, Zhanyao; Dehaen, Wim; Lyskawa, Joël; Woisel, Patrice; Hoogenboom, Richard

2017-07-25

A novel supramolecular miktoarm star polymer was successfully constructed in water from a pyridine end-decorated polymer (Py-PmDEGA) and a metalloporphyrin based star polymer (ZnTPP-(PEG) 4 ) via metal-ligand coordination. The Py-PmDEGA moiety was prepared via a combination of reversible addition-fragmentation chain transfer polymerization (RAFT) and subsequent aminolysis and Michael addition reactions to introduce the pyridine end-group. The ZnTPP(PEG) 4 star-polymer was synthesized by the reaction between tetrakis(p-hydroxyphenyl)porphyrin and toluenesulfonyl-PEG, followed by insertion of a zinc ion into the porphyrin core. The formation of a well-defined supramolecular AB 4 -type miktoarm star polymer was unambiguously demonstrated via UV-Vis spectroscopic titration, isothermal titration calorimetry (ITC) and diffusion ordered NMR spectroscopy (DOSY).

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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elasticity-dependent fast underwater adhesion demonstrated by macroscopic supramolecular assembly.

Science.gov (United States)

Ju, Guannan; Cheng, Mengjiao; Guo, Fengli; Zhang, Qian; Shi, Feng

2018-05-30

Macroscopic supramolecular assembly (MSA) is a recent progress in supramolecular chemistry to associate visible building blocks through non-covalent interactions in a multivalent manner. Although various substrates (e. g. hydrogels, rigid materials) have been used, a general design rule of building blocks in MSA systems and interpretation of the assembly mechanism are still lacking and urgently in demand. Here we design three model systems with varied modulus and correlated the MSA probability with the elasticity. Based on the effects of substrate deformability on multivalency, we have proposed an elastic-modulus-dependent rule that building blocks below a critical modulus of 2.5 MPa can achieve MSA for the used host/guest system. Moreover, this MSA rule applies well to the design of materials applicable for fast underwater adhesion: Soft substrates (0.5 MPa) can achieve underwater adhesion within 10 s with one magnitude higher strength than that of rigid substrates (2.5 MPa). © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular Systems and Chemical Reactions in Single-Molecule Break Junctions.

Science.gov (United States)

Li, Xiaohui; Hu, Duan; Tan, Zhibing; Bai, Jie; Xiao, Zongyuan; Yang, Yang; Shi, Jia; Hong, Wenjing

2017-04-01

The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

Fabrication of supramolecular frameworks by tuning the binding site ...

Indian Academy of Sciences (India)

Administrator

Fabrication of supramolecular frameworks by tuning the binding site of a tripodal ligand with d. 10 metal ions 803. Table 1. Crystal data and structure refinement parameters for 1 and 2. 1 .... e-mail: deposit@ccdc.cam.ac.uk web: http://www. ccdc. cam.ac.uk/deposit]. Supplementary figures and tables can be found in website ...

Supramolecular chemistry and chemical warfare agents: from fundamentals of recognition to catalysis and sensing.

Science.gov (United States)

Sambrook, M R; Notman, S

2013-12-21

Supramolecular chemistry presents many possible avenues for the mitigation of the effects of chemical warfare agents (CWAs), including sensing, catalysis and sequestration. To-date, efforts in this field both to study fundamental interactions between CWAs and to design and exploit host systems remain sporadic. In this tutorial review the non-covalent recognition of CWAs is considered from first principles, including taking inspiration from enzymatic systems, and gaps in fundamental knowledge are indicated. Examples of synthetic systems developed for the recognition of CWAs are discussed with a focus on the supramolecular complexation behaviour and non-covalent approaches rather than on the proposed applications.

Synthesis and evaluation of amphiphilic peptides as nanostructures and drug delivery tools

Science.gov (United States)

Sayeh, Naser Ali

systems can affect the drug delivery efficiency. The result of this work provided insights about optimizing the amphiphilic cyclic-linear trizaolyl peptides can be used to design compounds with more efficient drug delivery capabilities. Chapter 3. MANUSCRIPT II. The objective of this Chapter was to synthesize a different series of amphiphilic peptides for different objectives. First, the amphiphilic trizaolyl peptides in Chapter I were systematically modified by increasing the number of arginine and tryptophan sequence in cyclic and linear peptides. The rationale for the modification was to enhance the possibility of interaction with the cell membrane and therefore improving the cellular uptake process. Moreover, a new class of amphiphilic peptides consist of tryptophan and glutamic acid were conjugated with a peptide containing arginine and lysine residues using Fmoc chemistry. These peptides have an amide bond that generates more flexibility compared to a triazole ring. The chemical and biological properties will be evaluated in future and compared with amphiphilic triazolyl peptides. Finally, additional fatty acids with different length chains were conjugated with positively charged peptides to be evaluated as antibacterial agents. Stearic acid (C16) and myristic acid (C14) were conjugated with a peptides consisting of arginine azide and lysine amino acids to enhance the antibacterial activity. In summary, the work in this dissertation provided insights about the synthesis and characterization of a new class of amphiphilic triazolyl peptides as drug delivery carriers and amphiphilic peptides as antibacterial agents. Molecular modeling was used to explain why triazolyl peptides were unable to enhance the delivery of small molecule drugs compared to the previously synthesized cyclic peptides [WR]4 (Chapter 2) Modification of synthesized peptides in Chapter 1, by addition of more positively charged amino acids or reducing the rigidity by incorporating amide bonds instead

Methotrexate-Loaded Four-Arm Star Amphiphilic Block Copolymer Elicits CD8+ T Cell Response against a Highly Aggressive and Metastatic Experimental Lymphoma.

Science.gov (United States)

Hira, Sumit Kumar; Ramesh, Kalyan; Gupta, Uttam; Mitra, Kheyanath; Misra, Nira; Ray, Biswajit; Manna, Partha Pratim

2015-09-16

We have synthesized a well-defined four-arm star amphiphilic block copolymer [poly(DLLA)-b-poly(NVP)]4 [star-(PDLLA-b-PNVP)4] that consists of D,L-lactide (DLLA) and N-vinylpyrrolidone (NVP) via the combination of ring-opening polymerization (ROP) and xanthate-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization. Synthesis of the polymer was verified by 1H NMR spectroscopy and gel permeation chromatography (GPC). The amphiphilic four-arm star block copolymer forms spherical micelles in water as demonstrated by transmission electron microscopy (TEM) and 1H NMR spectroscopy. Pyrene acts as a probe to ascertain the critical micellar concentration (cmc) by using fluorescence spectroscopy. Methotrexate (MTX)-loaded polymeric micelles of star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer were prepared and characterized by fluorescence and TEM studies. Star-(PDLLA15-b-PNVP10)4 copolymer was found to be significantly effective with respect to inhibition of proliferation and lysis of human and murine lymphoma cells. The amphiphilic block copolymer causes cell death in parental and MTX-resistant Dalton lymphoma (DL) and Raji cells. The formulation does not cause hemolysis in red blood cells and is tolerant to lymphocytes compared to free MTX. Therapy with MTX-loaded star-(PDLLA15-b-PNVP10)4 amphiphilic block copolymer micelles prolongs the life span of animals with neoplasia by reducing the tumor load, preventing metastasis and augmenting CD8+ T cell-mediated adaptive immune responses.

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

Transfection of small numbers of human endothelial cells by electroporation and synthetic amphiphiles

NARCIS (Netherlands)

van Leeuwen, E B; van der Veen, A Y; Hoekstra, D; Engberts, J B; Halie, M R; van der Meer, J; Ruiters, M H

OBJECTIVES: This study compared the efficiency of electroporation and synthetic amphiphiles. (SAINT-2pp/DOPE) in transfecting small numbers of human endothelial cells. METHODS AND RESULTS: Optimal transfection conditions were tested and appeared to be 400 V and 960 microF for electroporation and a

Immunochemically identical hydrophilic and amphiphilic forms of the bovine adrenomedullary dopamine beta-hydroxylase

DEFF Research Database (Denmark)

Bjerrum, Ole Jannik; Helle, K B; Bock, Elisabeth Marianne

1979-01-01

. The dopamine beta-hydroxylases of the buffer and membrane fractions were antigenically identical, but differed in their amphiphilicity, as demonstrated by the change in precipitation patterns on removal of Triton X-100 from the gel, on charge-shift crossed immunoelectrophoresis and on crossed hydrophobic...

Dielectric electroactive polymers comprising an ionic supramolecular structure

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to an ionic interpenetrating polymer network comprising at least one elastomer and an ionic supramolecular structure comprising the reaction product of at least two chemical compounds wherein each of said compounds has at least two functional groups and wherein said ...... compounds are able to undergo Lewis acid-base reactions. The interpenetrating polymer network may be used as dielectric electroactive polymers (DEAPs) having a high dielectric permittivity....

Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

KAUST Repository

Li, Zhong’ an; Mukhopadhyay, Sukrit; Jang, Sei-Hum; Bredas, Jean-Luc; Jen, Alex K.-Y.

2015-01-01

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.

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.

Multiple cationic amphiphiles induce a Niemann-Pick C phenotype and inhibit Ebola virus entry and infection.

Directory of Open Access Journals (Sweden)

Charles J Shoemaker

Full Text Available Ebola virus (EBOV is an enveloped RNA virus that causes hemorrhagic fever in humans and non-human primates. Infection requires internalization from the cell surface and trafficking to a late endocytic compartment, where viral fusion occurs, providing a conduit for the viral genome to enter the cytoplasm and initiate replication. In a concurrent study, we identified clomiphene as a potent inhibitor of EBOV entry. Here, we screened eleven inhibitors that target the same biosynthetic pathway as clomiphene. From this screen we identified six compounds, including U18666A, that block EBOV infection (IC(50 1.6 to 8.0 µM at a late stage of entry. Intriguingly, all six are cationic amphiphiles that share additional chemical features. U18666A induces phenotypes, including cholesterol accumulation in endosomes, associated with defects in Niemann-Pick C1 protein (NPC1, a late endosomal and lysosomal protein required for EBOV entry. We tested and found that all six EBOV entry inhibitors from our screen induced cholesterol accumulation. We further showed that higher concentrations of cationic amphiphiles are required to inhibit EBOV entry into cells that overexpress NPC1 than parental cells, supporting the contention that they inhibit EBOV entry in an NPC1-dependent manner. A previously reported inhibitor, compound 3.47, inhibits EBOV entry by blocking binding of the EBOV glycoprotein to NPC1. None of the cationic amphiphiles tested had this effect. Hence, multiple cationic amphiphiles (including several FDA approved agents inhibit EBOV entry in an NPC1-dependent fashion, but by a mechanism distinct from that of compound 3.47. Our findings suggest that there are minimally two ways of perturbing NPC1-dependent pathways that can block EBOV entry, increasing the attractiveness of NPC1 as an anti-filoviral therapeutic target.

Terpyridine modified poly(vinyl chloride) : possibilities for supramolecular grafting and crosslinking

NARCIS (Netherlands)

Meier, M.A.R.; Schubert, U.S.

2003-01-01

Commercially available poly(vinyl chloride) (PVC) was covalently modified with terpyridine supramolecular binding units in a two-step reaction. First, PVC was modified with aromatic thiols to introduce OH functionalities into the polymer backbone, which were subsequently reacted with an

A pH-responsive supramolecular polymer gel as an enteric elastomer for use in gastric devices

Science.gov (United States)

Zhang, Shiyi; Bellinger, Andrew M.; Glettig, Dean L.; Barman, Ross; Lee, Young-Ah Lucy; Zhu, Jiahua; Cleveland, Cody; Montgomery, Veronica A.; Gu, Li; Nash, Landon D.; Maitland, Duncan J.; Langer, Robert; Traverso, Giovanni

2015-10-01

Devices resident in the stomach--used for a variety of clinical applications including nutritional modulation for bariatrics, ingestible electronics for diagnosis and monitoring, and gastric-retentive dosage forms for prolonged drug delivery--typically incorporate elastic polymers to compress the devices during delivery through the oesophagus and other narrow orifices in the digestive system. However, in the event of accidental device fracture or migration, the non-degradable nature of these materials risks intestinal obstruction. Here, we show that an elastic, pH-responsive supramolecular gel remains stable and elastic in the acidic environment of the stomach but can be dissolved in the neutral-pH environment of the small and large intestines. In a large animal model, prototype devices with these materials as the key component demonstrated prolonged gastric retention and safe passage. These enteric elastomers should increase the safety profile for a wide range of gastric-retentive devices.

Colloidal chirality in wormlike micellar systems exclusively originated from achiral species: Role of secondary assembly and stimulus responsivity.

Science.gov (United States)

Zhao, Wenrong; Hao, Jingcheng

2016-09-15

Colloidal chirality in wormlike micellar systems exclusively originated from achiral species and discussion of the role of secondary assembly of fiber-like aggregates in chirality generation were presented in this paper. Herein, formation of colloidal wormlike micelles for the first time incorporated chirality and redox-responsiveness into one design via noncovalent interaction. A dual-stimuli-responsive gel of wormlike micelles which were designed by employing a dual-responsive cationic surfactant (FTMA) and a strong gelator (AzoNa4) and regulated by redox reaction and host-guest inclusion is presented. Both the redox and host-guest interaction play an important role in regulating the viscosity and supramolecular chirality of gels of the wormlike micelles. The supramolecular chirality and viscosity of the wormlike micelle gels were switched reversibly by exerting chemical redox onto the ferrocenyl groups. For the amphiphile FTMA containing redox-active ferrocenyl group, reversible control of the oxidation state of ferrocenyl groups leads to the charge and hydrophobicity changes of FTMA, therefore change its self-assembly behavior. Of equal interest, β-CD successfully detached the wormlike micelles via the recognition-inclusion behavior with FTMA and invalidate the H-bond and hydrophobic interaction between FTMA and AzoH4. This designed system provides a new strategy to tune the supramolecular chirality of colloidal aggregates and explore the specific packing mode detail within the micelles or the secondary assembly of the inter-micelles. We anticipate this dual-responsive H-bond-directed chiral gel switch could propose a new strategy when researchers designing new, multi-responsive functional gel materials. Copyright © 2016 Elsevier Inc. All rights reserved.

Amphiphilic block copolymers as efficiency boosters in microemulsions a SANS investigation of the role of polymers

CERN Document Server

Endo, H; Mihailescu, M; Monkenbusch, M; Gompper, G; Richter, D; Jakobs, B; Sottmann, T; Strey, R

2002-01-01

The effect of amphiphilic block copolymers on ternary microemulsions (water, oil and non-ionic surfactant) is investigated. Small amounts of PEP-PEO block copolymer lead to a dramatic expansion of the one-phase region where water and oil can be solubilized by the mediation of surfactant molecules. Small-angle neutron-scattering experiments employing a high-precision two-dimensional contrast-variation technique demonstrate that the polymer is distributed uniformly on the surfactant membrane, where it modifies the membrane curvature elasticity. Furthermore, a new approach to determine the bending rigidity of an amphiphilic membrane is proposed, which is precise enough to measure the logarithmic scale dependence of the bending rigidity and its universal prefactor in bicontinuous microemulsions. (orig.)

Self-assembly of block copolymer-based ionic supramolecules based upon multi-tail amphiphiles

DEFF Research Database (Denmark)

Asad Ayoubi, M.; Almdal, Kristoffer; Zhu, K.

2015-01-01

Utilising simple acid-base titration chemistry, a new family of Linear-b-Amphiphilic Comb (L-b-AC) ionic supramolecules [Soft Matter 2013, 9, 1540-1555] featuring multi-tail side-chains have been synthesized and examined by synchrotron SAXS. To three different parent diblock copolymers of poly...

Novel amphiphilic poly(dimethylsiloxane) based polyurethane networks tethered with carboxybetaine and their combined antibacterial and anti-adhesive property

Science.gov (United States)

Jiang, Jingxian; Fu, Yuchen; Zhang, Qinghua; Zhan, Xiaoli; Chen, Fengqiu

2017-08-01

The traditional nonfouling materials are powerless against bacterial cells attachment, while the hydrophobic bactericidal surfaces always suffer from nonspecific protein adsorption and dead bacterial cells accumulation. Here, amphiphilic polyurethane (PU) networks modified with poly(dimethylsiloxane) (PDMS) and cationic carboxybetaine diol through simple crosslinking reaction were developed, which had an antibacterial efficiency of 97.7%. Thereafter, the hydrolysis of carboxybetaine ester into zwitterionic groups brought about anti-adhesive properties against bacteria and proteins. The surface chemical composition and wettability performance of the PU network surfaces were investigated by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and contact angle analysis. The surface distribution of PDMS and zwitterionic segments produced an obvious amphiphilic heterogeneous surface, which was demonstrated by atomic force microscopy (AFM). Enzyme-linked immunosorbent assays (ELISA) were used to test the nonspecific protein adsorption behaviors. With the advantages of the transition from excellent bactericidal performance to anti-adhesion and the combination of fouling resistance and fouling release property, the designed PDMS-based amphiphilic PU network shows great application potential in biomedical devices and marine facilities.

Anchoring cationic amphiphiles for nucleotide delivery: significance of DNA release from cationic liposomes for transfection.

Science.gov (United States)

Hirashima, Naohide; Minatani, Kazuhiro; Hattori, Yoshifumi; Ohwada, Tomohiko; Nakanishi, Mamoru

2007-06-01

We have designed and synthesized lithocholic acid-based cationic amphiphile molecules as components of cationic liposomes for gene transfection (lipofection). To study the relationship between the molecular structures of those amphiphilic molecules, particularly the extended hydrophobic appendant (anchor) at the 3-hydroxyl group, and transfection efficiency, we synthesized several lithocholic and isolithocholic acid derivatives, and examined their transfection efficiency. We also compared the physico-chemical properties of cationic liposomes prepared from these derivatives. We found that isolithocholic acid derivatives exhibit higher transfection efficiency than the corresponding lithocholic acid derivatives. This result indicates that the orientation and extension of hydrophobic regions influence the gene transfection process. Isolithocholic acid derivatives showed a high ability to encapsulate DNA in a compact liposome-DNA complex and to protect it from enzymatic degradation. Isolithocholic acid derivatives also facilitated the release of DNA from the liposome-DNA complex, which is a crucial step for DNA entry into the nucleus. Our results show that the transfection efficiency is directly influenced by the ability of the liposome complex to release DNA, rather than by the DNA-encapsulating ability. Molecular modeling revealed that isolithocholic acid derivatives take relatively extended conformations, while the lithocholic acid derivatives take folded structures. Thus, the efficiency of release of DNA from cationic liposomes in the cytoplasm, which contributes to high transfection efficiency, appears to be dependent upon the molecular shape of the cationic amphiphiles.

Peptide amphiphile nanoparticles enhance the immune response against a CpG-adjuvanted influenza antigen

NARCIS (Netherlands)

Zope, H.; Quer, C.B.; Bomans, P.H.H.; Sommerdijk, N.A.J.M.; Kros, A.; Jiskoot, W.

2014-01-01

Cationic peptide amphiphile nanoparticles are employed for co-delivery of immune modulator CpG and antigen. This results in better targeting to the antigen presenting cells and eliciting strong Th1 response, which is effective against the intracellular pathogens.

Coherent states field theory in supramolecular polymer physics

Science.gov (United States)

Fredrickson, Glenn H.; Delaney, Kris T.

2018-05-01

In 1970, Edwards and Freed presented an elegant representation of interacting branched polymers that resembles the coherent states (CS) formulation of second-quantized field theory. This CS polymer field theory has been largely overlooked during the intervening period in favor of more conventional "auxiliary field" (AF) interacting polymer representations that form the basis of modern self-consistent field theory (SCFT) and field-theoretic simulation approaches. Here we argue that the CS representation provides a simpler and computationally more efficient framework than the AF approach for broad classes of reversibly bonding polymers encountered in supramolecular polymer science. The CS formalism is reviewed, initially for a simple homopolymer solution, and then extended to supramolecular polymers capable of forming reversible linkages and networks. In the context of the Edwards model of a non-reacting homopolymer solution and one and two-component models of telechelic reacting polymers, we discuss the structure of CS mean-field theory, including the equivalence to SCFT, and show how weak-amplitude expansions (random phase approximations) can be readily developed without explicit enumeration of all reaction products in a mixture. We further illustrate how to analyze CS field theories beyond SCFT at the level of Gaussian field fluctuations and provide a perspective on direct numerical simulations using a recently developed complex Langevin technique.

Supramolecular nano-sniffers for ultrasensitive detection of formaldehyde.

Science.gov (United States)

Akshath, Uchangi Satyaprasad; Bhatt, Praveena

2018-02-15

Supramolecular nanoparticle hybrids for biosensing of analytes have been a major focus due to their tunable optical and surface properties. Quantum dots-Gold nanoparticle (QDs-GNP) based FRET probes involving turn on/off principles have gained immense interest due to their specificity and sensitivity. Recent focus is on applying these supramolecular hybrids for enzyme operated biosensors that can specifically turn-on fluorescence induced by co-factor or product formed from enzymatic reaction. The present study focuses on locking and unlocking the interaction between QD-GNP pair leading to differential fluorescent properties. Cationic GNPs efficiently quenched the anionic QD fluorescence by forming nanoparticle hybrid. Quenching interaction between QD-GNP pair was unlocked by NADH leading to QD fluorescence turn-on. This phenomenon was applied for the successful detection of formaldehyde using NAD + dependent formaldehyde dehydrogenase. The proposed nano-sniffer could successfully detect formaldehyde from 0.001 to 100000ng/mL (R 2 = 0.9339) by the turn off-turn on principle. It could also detect formaldehyde in fruit juice and wine samples indicating its stability and sensitivity in real samples. The proposed nanoprobe can have wide applications in developing enzyme biosensors in future. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of Cellulose Supramolecular Structures Between Nanocrystals of Different Origins

Science.gov (United States)

Umesh P. Agarwal; Richard S. Reiner; Christopher G. Hunt; Jeffery Catchmark; E. Johan Foster; Akira Isogai

2015-01-01

In this study, morphologies and supramolecular structures of CNCs from wood-pulp, cotton, bacteria, tunicate, and cladophora were investigated. TEM was used to study the morphological aspects of the nanocrystals whereas Raman spectroscopy provided information on the cellulose molecular structure and its organization within a CNC. Dimensional differences between the...

Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

Energy Technology Data Exchange (ETDEWEB)

Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo, E-mail: case@fct.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Presidente Prudente, SP (Brazil). Dept. de Fisica

2017-07-15

The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

Physical vapor deposited films of a perylene derivative: supramolecular arrangement and thermal stability

International Nuclear Information System (INIS)

Fernandes, Jose Diego; Alessio, Priscila; Silva, Matheus Rodrigues Medeiros; Aroca, Ricardo Flavio; Souza, Agda Eunice de; Constantino, Carlos Jose Leopoldo

2017-01-01

The analysis of supramolecular arrangement is essential to understand the role of this key factor on the optical and electrical properties of organic thin films. In this work, thin solid films of bis(phenethylimido) perylene (PhPTCD) fabricated using physical vapor deposition (PVD) technique (thermal evaporation), deposited simultaneously onto different substrates (Ag mirror, Ge, and quartz plates) contingent on the characterization technique. The main objective is to study the PhPTCD supramolecular arrangement and the thermal stability of this arrangement in PVD films. The ultraviolet-visible absorption reveals a controlled growth of the PVD films, and the micro-Raman scattering data show that the PhPTCD molecule is not thermally degraded in the conditions of these experiments. The microscopy also shows a homogeneous morphological surface of the PVD film at macro and micro scales, with molecular aggregates at nanoscale. Besides, the PVD film roughness does not follow substrate roughness. The X-ray diffraction indicates a crystalline structure for PhPTCD powder and an amorphous form for PhPTCD PVD film. The infrared absorption spectroscopy points to a preferential flat-on organization of the molecules in the PVD films. In addition, the annealing process (200 deg C for 20 minutes) does not affect the supramolecular arrangement of the PhPTCD PVD films. (author)

In-vitro cytotoxic activities of poly(2-ethyl-2-oxazoline-based amphiphilic block copolymers prepared by CuAAC click chemistry

Directory of Open Access Journals (Sweden)

S. Gulyuz

2018-02-01

Full Text Available Synthesis and characterization of well-defined amphiphilic block copolymers containing poly(2-ethyl-2-oxazoline as hydrophilic block and poly(ε-caprolactone or poly(L-lactide as hydrophobic block is achieved by copper-catalyzed azide-alkyne cycloaddition (CuAAC click chemistry. The clickable precursors, α-alkyne-functionalized poly(ε-caprolactone and poly(L-lactide and ω-azido-functionalized poly(2-ethyl-2-oxazoline are simply prepared and joined using copper sulfate/ascorbic acid catalyst system at room temperature. The structures of precursors and amphiphilic block copolymers are characterized by spectroscopic, chromatographic and thermal analyses. The cytotoxic activities of resulting amphiphilic block copolymers and their precursors are investigated in the prostate epithelial and cancer cells under in-vitro conditions. The treatment of the healthy prostate epithelial cell line PNT1A reveals that no significant cytotoxicity, whereas some significant toxic effects on the prostate cancer cell lines are observed.

Amplification of chirality in helical supramolecular polymers: the majority-rules principle.

NARCIS (Netherlands)

Gestel, van J.A.M.

2004-01-01

Amplification of chirality, being a strongly nonlinear response of the optical activity of helical polymers to a small (net) amount of optically active material, has recently been discovered in supramolecular copolymers. Apart from the sergeants-and-soldiers type we discussed in earlier work,

Ga(III) chelates of amphiphilic DOTA-based ligands: synthetic route and in vitro and in vivo studies

International Nuclear Information System (INIS)

Fontes, Andre; Prata, M. Isabel M.; Geraldes, Carlos F.G.C.; Andre, Joao P.

2011-01-01

In this work, we report on a synthetic strategy using amphiphilic DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-based chelators bearing a variable-sized α-alkyl chain at one of the pendant acetate arms (from 6 to 14 carbon atoms), compatible with their covalent coupling to amine-bearing biomolecules. The amphiphilic behavior of the micelles-forming Ga(III) chelates (critical micellar concentration), their stability in blood serum and their lipophilicity (logP) were investigated. Biodistribution studies with the 67 Ga-labeled chelates were performed in Wistar rats, which showed a predominant liver uptake with almost no traces of the radiochelates in the body after 24 h.

PEG-bis phosphonic acid based ionic supramolecular structures

DEFF Research Database (Denmark)

Gonzalez, Lidia; Skov, Anne Ladegaard; Hvilsted, Søren

2014-01-01

. The resulting ionic assemblies are very comprehensively characterized by ATR-FTIR, proton, and carbon-13 NMR spectroscopy that unequivocally demonstrate the ionic network formation through ammonium phophonates. The resulting salt and ionic networks are additionally analyzed by differential scanning calorimetry...... and thermogravimetric analysis. The conclusion is that mixing the virgin components at room temperature spontaneously form either a salt or ionic supramolecular networks. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

Unconventional, amphiphilic polymers based on chiral polyethylene oxide derivatives I. Synthesis and Characterization.

NARCIS (Netherlands)

Janssen, H.M.; Peeters, E.; Zundert, van M.F.; Genderen, van M.H.P.; Meijer, E.W.

1997-01-01

The first representatives of a new class of synthetic, amphiphilic polymers based on poly(ethylene oxide) are introduced. These polymers are constituted in a similar way to that for coiled-coil-forming peptides: the polymers possess a regular repeat of apolar (A) residues in a polar (P) sequence of

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.

Insight into the chiral induction in supramolecular stacks through preferential chiral salvation

NARCIS (Netherlands)

George, S.J.; Tomovic, Z.; Schenning, A.P.H.J.; Meijer, E.W.

2011-01-01

Preferred handedness in the supramolecular chirality of self-assembled achiral oligo(p-phenylenevinylene) (OPV) derivatives is induced by chiral solvents and spectroscopic probing provides insight into the mechanistic aspects of this chiral induction through chiral solvation

Photoluminescence Spectra of Self-Assembling Helical Supramolecular Assemblies: A Theoretical Study

NARCIS (Netherlands)

van Dijk, Leon; Kersten, Sander P.; Jonkheijm, Pascal; van der Schoot, Paul; Bobbert, Peter A.

2008-01-01

The reversible assembly of helical supramolecular polymers of chiral molecular building blocks is known to be governed by the interplay between mass action and the competition between weakly and strongly bound states of these building blocks. The highly co-operative transition from free monomers at

Novel self-associative and multiphase nanostructured soft carriers based on amphiphilic hyaluronic acid derivatives

DEFF Research Database (Denmark)

Eenschooten, Corinne; Vaccaro, Andrea; Delie, Florence

2012-01-01

The purpose of the present study was to investigate the physicochemical properties in aqueous media of amphiphilic hyaluronic acid (HA) derivatives obtained by reaction of HA’s hydroxyl groups with octenyl succinic anhydride (OSA). The self-associative properties of the resulting octenyl succinic...

Synthesis of amphiphilic macrocyclic molecules from family of aza-porphyrins and study in Langmuir-Blodgett films; Synthese de molecules macrocycliques amphiphiles de la famille des azaporphyrines et etude en films de Langmuir-Blodgett

Energy Technology Data Exchange (ETDEWEB)

Palacin, Serge

1988-03-04

The cellular automata, also called formal neurons, directly inspired by the knowledge concerning the nervous system, are able to mimic some basic processes of brain, as shape recognition, connecting memory, information sorting... This work aims to build a molecular structure able to fit the working rules of a bidimensional cellular automata. So, amphiphilic molecules belonging to the aza-porphyrin family are synthesized and organized into a planar paving by the Langmuir-Blodgett technique. The regular structure of the outcoming ultra-thin films is studied by linear dichroism and anisotropic electron spin resonance. The physico-chemical behaviour of the amphiphilic molecules is studied and brings about an explanation of the redox phenomena which are observed on the monomolecular film on the water surface. So are we able to outline the future chemical addressing ways of the bidimensional cellular automata. In the end of this dissertation, different ways likely to insure covalent bindings between the active sites and allow the transfer of information within the cellular network are discussed. (author) [French] Les reseaux d'automates, aussi appeles neurones formels, directement inspires par les connaissances nouvelles concernant le fonctionnement du systeme nerveux, sont a l'heure actuelle capables de reproduire certaines operations fondamentales du cerveau, telles que la reconnaissance de forme, la memoire associative, le tri d'information... Le travail a pour but de realiser une structure moleculaire susceptible d'obeir aux regles de fonctionnement d'un automate cellulaire bi-dimensionnel. Dans ce but, des molecules amphiphiles de la famille des azaporphyrines sont synthetisees et organisees en un pavage plan par la methode de Langmuir-Blodgett. La structure reguliere des films ultraminces obtenus est determinee par dichroisme lineaire et resonance paramagnetique electronique anisotrope. Les caracteristiques physico-chimiques des molecules amphiphiles sont etudiees

A new class of amphiphiles: annelids; Une nouvelle classe d'amphiphiles: les annelides

Energy Technology Data Exchange (ETDEWEB)

Markovitsi, Dimitra

1983-12-14

This research thesis presents annelids, organometallic compounds which may form into organised phases. The author describes the synthesis of an amphipathic ligand of its cobaltic and cupric complexes. The formation of micelles and of thermotropic and lyotropic liquid crystals is highlighted. The copper (II) annelid environment is studied by electronic paramagnetic resonance spectroscopy. The author demonstrates, in micellar phase, the effect of molecular cooperativity on acid-base balance, on metallic ion complexation, on the photo-sensitized electronic transfer, and on the formation of poly-nuclear complexes [French] Les annelides, composes organometalliques susceptibles de former des phases organisees, sont presentes. La synthese d'un ligand amphipathique et de ses complexes cobaltique et cuivrique est decrite. La formation de micelles et de cristaux liquides, thermotropes et lyotropes, a l'aide de ces amphiphiles, est mise en evidence. L'environnement de l'annelide de cuivre (II) est etudie par spectroscopie de resonance paramagnetique electronique. L'effet de la cooperativite moleculaire sur l'equilibre acidobasique, sur la complexation des ions metalliques, sur le transfert electronique photosensibilise et sur la formation des complexes polynucleaires est demontre en phase micellaire. (auteur)

Noncovalent assembly. A rational strategy for the realization of chain-growth supramolecular polymerization.

Science.gov (United States)

Kang, Jiheong; Miyajima, Daigo; Mori, Tadashi; Inoue, Yoshihisa; Itoh, Yoshimitsu; Aida, Takuzo

2015-02-06

Over the past decade, major progress in supramolecular polymerization has had a substantial effect on the design of functional soft materials. However, despite recent advances, most studies are still based on a preconceived notion that supramolecular polymerization follows a step-growth mechanism, which precludes control over chain length, sequence, and stereochemical structure. Here we report the realization of chain-growth polymerization by designing metastable monomers with a shape-promoted intramolecular hydrogen-bonding network. The monomers are conformationally restricted from spontaneous polymerization at ambient temperatures but begin to polymerize with characteristics typical of a living mechanism upon mixing with tailored initiators. The chain growth occurs stereoselectively and therefore enables optical resolution of a racemic monomer. Copyright © 2015, American Association for the Advancement of Science.

Supramolecular Lego assembly towards three-dimensional multi-responsive hydrogels.

Science.gov (United States)

Ma, Chunxin; Li, Tiefeng; Zhao, Qian; Yang, Xuxu; Wu, Jingjun; Luo, Yingwu; Xie, Tao

2014-08-27

Inspired by the assembly of Lego toys, hydrogel building blocks with heterogeneous responsiveness are assembled utilizing macroscopic supramolecular recognition as the adhesion force. The Lego hydrogel provides 3D transformation upon pH variation. After disassembly of the building blocks by changing the oxidation state, they can be re-assembled into a completely new shape. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure and reactivity in amphiphile-water micelles

International Nuclear Information System (INIS)

Chevalier, Yves

1985-01-01

Following a review of the general properties of micelles, this report contains two parts: - A structural study of octylphosphate micelles. Important structural changes have been evidenced by mean of small angle neutron scattering as the electrical charge of the interface is varied. The NMR relaxation study of the conformation of the hydrocarbon chains has shown that the micellar core is disordered in contrast with the interface which is rather structured. The diffusion motions in the interface and the segmental motions of the chains are fast. - Studies on the reactivity in micelles have been carried out. A large micellar effect on the complexation of transition ions by amphiphilic ligands is evidenced. The problem of solute localization in micelles is developed with few examples. (author) [fr

Structures of self-assembled amphiphilic peptide-heterodimers: effects of concentration, pH, temperature and ionic strength

KAUST Repository

Luo, Zhongli

2010-01-01

The amphiphilic double-tail peptides AXG were studied regarding secondary structure and self-assembly in aqueous solution. The two tails A = Ala 6 and G = Gly6 are connected by a central pair X of hydrophilic residues, X being two aspartic acids in ADG, two lysines in AKG and two arginines in ARG. The peptide AD (Ala6Asp) served as a single-tail reference. The secondary structure of the four peptides was characterized by circular dichroism spectroscopy under a wide range of peptide concentrations (0.01-0.8 mM), temperatures (20-98 °C), pHs (4-9.5) and ionic strengths. In salt-free water both ADG and AD form a β-sheet type of structure at high concentration, low pH and low temperature, in a peptide-peptide driven assembly of individual peptides. The transition has a two-state character for ADG but not for AD, which indicates that the added tail in ADG makes the assembly more cooperative. By comparison the secondary structures of AKG and ARG are comparatively stable over the large range of conditions covered. According to dynamic light scattering the two-tail peptides form supra-molecular aggregates in water, but high-resolution AFM-imaging indicate that ordered (self-assembled) structures are only formed when salt (0.1 M NaCl) is added. Since the CD-studies indicate that the NaCl has only a minor effect on the peptide secondary structure we propose that the main role of the added salt is to screen the electrostatic repulsion between the peptide building blocks. According to the AFM images ADG and AKG support a correlation between nanofibers and a β-sheet or unordered secondary structure, whereas ARG forms fibers in spite of lacking β-sheet structure. Since the AKG and ARG double-tail peptides self-assemble into distinct nanostructures while their secondary structures are resistant to environment factors, these new peptides show potential as robust building blocks for nano-materials in various medical and nanobiotechnical applications. © 2010 The Royal Society

Methodology for studying molecular and supramolecular structures of coals and carbonaceous materials

Energy Technology Data Exchange (ETDEWEB)

G.B. Skripchenko [Russian Academy of Sciences, Moscow (Russian Federation). Russia Institute for Fossil Fuels - Science and Technology Center for Complex Processing of Solid Fossil Fuels

2009-07-01

Those studying coals have to account for petrographic nonuniformity (the optical structural level), different types of chemical bonding between structural fragments, the existence of aromatic clusters in the organic matter, the appearance of a supramolecular order between aromatic clusters, and further orientation ordering of crystallites under the action of the geological pressure. Combinations of conventional chemical strategies with advanced physicochemical methods, such as IR, NMR, EPR, and X-ray spectroscopy; X-ray diffraction; electronic and scanning microscopy; and some others, are pertinent for structure determination. The appearance of supramolecular structures is a manifestation of molecular-level structural rearrangements, which are characteristic of coals, cokes, pitches, and various pyrolytic carbons. This necessitates the use of optical, electronic, and scanning microscopy along with other chemical methods. The occurrence of mineral components in coals can appreciably limit the resolution of IR spectroscopy and X-ray crystallography.

Water-soluble building blocks for terpyridine-containing supramolecular polymers : synthesis, complexation, and pH stability studies of poly(ethylene oxide) moieties

NARCIS (Netherlands)

Lohmeijer, B.G.G.; Schubert, U.S.

2003-01-01

Poly(ethylene oxide) of various molecular weights ([bar M ]n = 3 000, 5 200, 10 000, 16 500 g · mol-1) has been modified with terpyridine end groups as building blocks for water-soluble metallo-supramolecular polymers. Metallo-supramolecular A-A homopolymers have been prepared and characterized by

Differential thermodynamic signature of carbon nanomaterials using amphiphilic micellar probe

Science.gov (United States)

Bhattacharyya, Tamoghna; Dasgupta, Anjan Kr

2018-04-01

The thermodynamic signature of single-wall carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rG-O) using amphiphilic micellar probe has been explored. The study reveals an intricate correlation between nano-surface topology and calorimetric profile of SWCNTs, MWCNTs and rG-O. The critical micelle concentration (CMC) is found to be sensitive to the topological diversity of nanomaterials. The study explores a thermodynamic approach to characterize the nano-surface topology of SWCNTs, MWCNTs and graphene surface.

Is Supramolecular Filament Chirality the Underlying Cause of Major Morphology Differences in Amyloid Fibrils?

Science.gov (United States)

2015-01-01

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for “normal” left-hand-helical filaments and below pH 2 for “reversed” right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218–289) prion, and a short polypeptide fragment of transthyretin, TTR (105–115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases. PMID:24484302

Is supramolecular filament chirality the underlying cause of major morphology differences in amyloid fibrils?

Science.gov (United States)

Kurouski, Dmitry; Lu, Xuefang; Popova, Ludmila; Wan, William; Shanmugasundaram, Maruda; Stubbs, Gerald; Dukor, Rina K; Lednev, Igor K; Nafie, Laurence A

2014-02-12

The unique enhanced sensitivity of vibrational circular dichroism (VCD) to the formation and development of amyloid fibrils in solution is extended to four additional fibril-forming proteins or peptides where it is shown that the sign of the fibril VCD pattern correlates with the sense of supramolecular filament chirality and, without exception, to the dominant fibril morphology as observed in AFM or SEM images. Previously for insulin, it has been demonstrated that the sign of the VCD band pattern from filament chirality can be controlled by adjusting the pH of the incubating solution, above pH 2 for "normal" left-hand-helical filaments and below pH 2 for "reversed" right-hand-helical filaments. From AFM or SEM images, left-helical filaments form multifilament braids of left-twisted fibrils while the right-helical filaments form parallel filament rows of fibrils with a flat tape-like morphology, the two major classes of fibril morphology that from deep UV resonance Raman scattering exhibit the same cross-β-core secondary structure. Here we investigate whether fibril supramolecular chirality is the underlying cause of the major morphology differences in all amyloid fibrils by showing that the morphology (twisted versus flat) of fibrils of lysozyme, apo-α-lactalbumin, HET-s (218-289) prion, and a short polypeptide fragment of transthyretin, TTR (105-115), directly correlates to their supramolecular chirality as revealed by VCD. The result is strong evidence that the chiral supramolecular organization of filaments is the principal underlying cause of the morphological heterogeneity of amyloid fibrils. Because fibril morphology is linked to cell toxicity, the chirality of amyloid aggregates should be explored in the widely used in vitro models of amyloid-associated diseases.

Chiral Induction and amplification in supramolecular systems at the liquid-solid interface

NARCIS (Netherlands)

Xu, Hong; Ghijsens, E.; George, S.J.; Wolffs, M.; Tomovic, Z.; Schenning, A.P.H.J.; Feyter, de S.

2013-01-01

Chiral induction and amplification in surface-confined supramolecular monolayers are investigated at the liquid–solid interface. Scanning tunneling microscopy (STM) proves that achiral molecules can self-assemble into globally chiral patterns through a variety of approaches, including induction by

Self-assembling multivalency : supramolecular polymers assembled from monovalent mannose-labelled discotic molecules

NARCIS (Netherlands)

Petkau - Milroy, K.; Brunsveld, L.

2013-01-01

Supramolecular synthesis, the "bottom-up" construction of higher-order structures from monomeric building blocks, represents a flexible approach for the generation of multivalent materials. Here, monovalent building blocks decorated with a single bioactive ligand were synthesized. In water, these

Ga(III) chelates of amphiphilic DOTA-based ligands: synthetic route and in vitro and in vivo studies

Energy Technology Data Exchange (ETDEWEB)

Fontes, Andre [Centro de Quimica, Campus de Gualtar, Universidade do Minho, 4710-057, Braga (Portugal); Prata, M. Isabel M. [IBILI, Faculdade de Medicina, Universidade de Coimbra, 3548, Coimbra (Portugal); Geraldes, Carlos F.G.C. [Departamento de Ciencias da Vida, Faculdade de Ciencias e Tecnologia, Universidade de Coimbra, 3001-401, Coimbra (Portugal); Centro de Neurociencias e Biologia Celular, Universidade de Coimbra, 3001-401, Coimbra (Portugal); Andre, Joao P., E-mail: jandre@quimica.uminho.p [Centro de Quimica, Campus de Gualtar, Universidade do Minho, 4710-057, Braga (Portugal)

2011-04-15

In this work, we report on a synthetic strategy using amphiphilic DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-based chelators bearing a variable-sized {alpha}-alkyl chain at one of the pendant acetate arms (from 6 to 14 carbon atoms), compatible with their covalent coupling to amine-bearing biomolecules. The amphiphilic behavior of the micelles-forming Ga(III) chelates (critical micellar concentration), their stability in blood serum and their lipophilicity (logP) were investigated. Biodistribution studies with the {sup 67}Ga-labeled chelates were performed in Wistar rats, which showed a predominant liver uptake with almost no traces of the radiochelates in the body after 24 h.

Self-Assembly of Amphiphilic Block Copolypeptoids with C 2 -C 5 Side Chains in Aqueous Solution

KAUST Repository

Fetsch, Corinna

2014-12-22

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Nowadays, amphiphilic molecules play an important role in our life. In medical applications, amphiphilic block copolymers have attracted much attention as excipients in drug delivery systems. Here, the polymers are used as emulsifiers, micelles, or polymersomes with a hydrophilic corona block and a hydrophobic core or membrane. The aggregation behavior in aqueous solutions of a series of different amphiphilic block copolypeptoids comprising polysarcosine as a hydrophilic part is here reported. The formation of aggregates is investigated with 1H NMR spectroscopy and dynamic light scattering, and the determination of the critical micelle concentration (cmc) is performed using pyrene fluorescence spectroscopy. For the different block copolypeptoids cmc values ranging from 0.6 × 10-6 M to 0.1 × 10-3 M are found. The tendency to form micelles increases with increasing hydrophobicity at the nitrogen side chain in the hydrophobic moiety. Furthermore, in the case of the same hydrophobic side chain, a decreasing hydrophilic/lipophilic balance leads to the formation of larger aggregates. The aggregates formed in the buffer are able to solubilize the hydrophobic model compounds Reichardt\\'s dye and pyrene, and exhibit versatile microenvironments. Final investigations about the cytotoxicity reveal that the block copolypeptoids are well tolerated by mammalian cells up to high concentrations.

Chiral supramolecular organization from a sheet-like achiral gel: a study of chiral photoinduction.

Science.gov (United States)

Royes, Jorge; Polo, Víctor; Uriel, Santiago; Oriol, Luis; Piñol, Milagros; Tejedor, Rosa M

2017-05-31

Chiral photoinduction in a photoresponsive gel based on an achiral 2D architecture with high geometric anisotropy and low roughness has been investigated. Circularly polarized light (CPL) was used as a chiral source and an azobenzene chromophore was employed as a chiral trigger. The chiral photoinduction was studied by evaluating the preferential excitation of enantiomeric conformers of the azobenzene units. Crystallographic data and density functional theory (DFT) calculations show how chirality is transferred to the achiral azomaterials as a result of the combination of chiral photochemistry and supramolecular interactions. This procedure could be applied to predict and estimate chirality transfer from a chiral physical source to a supramolecular organization using different light-responsive units.

Linear Viscoelastic and Dielectric Relaxation Response of Unentangled UPy-Based Supramolecular Networks

DEFF Research Database (Denmark)

Shabbir, Aamir; Javakhishvili, Irakli; Cerveny, Silvina

2016-01-01

Supramolecular polymers possess versatile mechanical properties and a unique ability to respond to external stimuli. Understanding the rich dynamics of such associative polymers is essential for tailoring user-defined properties in many products. Linear copolymers of 2-methoxyethyl acrylate (MEA)...

Macromolecules containing bipyridine and terpyridine metal complexes: towards metallo-supramolecular polymers

NARCIS (Netherlands)

Schubert, U.S.; Eschbaumer, C.

2002-01-01

The ability of a broad range of N-heterocycles to act as very effective and stable complexation agents for several transition metal ions, such as cobalt(II), copper(II), nickel(II), and ruthenium(II), has long been known in analytical chemistry. This behavior was later utilized in supramolecular

In situ SERS detection of emulsifiers at lipid interfaces using label-free amphiphilic gold nanoparticles.

Science.gov (United States)

Li, Yue; Driver, Michael; Winuprasith, Thunnalin; Zheng, Jinkai; McClements, David Julian; He, Lili

2014-10-21

Herein, we fabricated amphiphilic gold nanoparticles (GNPs) that can self-assemble at oil-water interfaces. We applied those GNPs for in situ SERS detection of emulsifier molecules within the interfacial region of oil in water (O/W) emulsion systems.

Transfer and Dynamic Inversion of Coassembled Supramolecular Chirality through 2D-Sheet to Rolled-Up Tubular Structure.

Science.gov (United States)

Choi, Heekyoung; Cho, Kang Jin; Seo, Hyowon; Ahn, Junho; Liu, Jinying; Lee, Shim Sung; Kim, Hyungjun; Feng, Chuanliang; Jung, Jong Hwa

2017-12-13

Transfer and inversion of supramolecular chirality from chiral calix[4]arene analogs (3D and 3L) with an alanine moiety to an achiral bipyridine derivative (1) with glycine moieties in a coassembled hydrogel are demonstrated. Molecular chirality of 3D and 3L could transfer supramolecular chirality to an achiral bipyridine derivative 1. Moreover, addition of 0.6 equiv of 3D or 3L to 1 induced supramolecular chirality inversion of 1. More interestingly, the 2D-sheet structure of the coassembled hydrogels formed with 0.2 equiv of 3D or 3L changed to a rolled-up tubular structure in the presence of 0.6 equiv of 3D or 3L. The chirality inversion and morphology change are mainly mediated by intermolecular hydrogen-bonding interactions between the achiral and chiral molecules, which might be induced by reorientations of the assembled molecules, confirmed by density functional theory calculations.

Self-organization of a self-assembled supramolecular rectangle, square, and three-dimensional cage on Au111 surfaces.

Science.gov (United States)

Yuan, Qun-Hui; Wan, Li-Jun; Jude, Hershel; Stang, Peter J

2005-11-23

The structure and conformation of three self-assembled supramolecular species, a rectangle, a square, and a three-dimensional cage, on Au111 surfaces were investigated by scanning tunneling microscopy. These supramolecular assemblies adsorb on Au111 surfaces and self-organize to form highly ordered adlayers with distinct conformations that are consistent with their chemical structures. The faces of the supramolecular rectangle and square lie flat on the surface, preserving their rectangle and square conformations, respectively. The three-dimensional cage also forms well-ordered adlayers on the gold surface, forming regular molecular rows of assemblies. When the rectangle and cage were mixed together, the assemblies separated into individual domains, and no mixed adlayers were observed. These results provide direct evidence of the noncrystalline solid-state structures of these assemblies and information about how they self-organize on Au111 surfaces, which is of importance in the potential manufacturing of functional nanostructures and devices.

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.

Rapid fabrication of hierarchically structured supramolecular nanocomposite thin films in one minute

Energy Technology Data Exchange (ETDEWEB)

Xu, Ting; Kao, Joseph

2016-11-08

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. The assembly kinetics of supramolecular nanocomposite in thin films is 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 approximately one minute. Moreover, the strong wavelength dependent optical anisotropy in the nanocomposite highlights their potential applications for light manipulation and information transmission. The present invention opens a new avenue in designing manufacture-friendly continuous processing for the fabrication of functional nanocomposite thin films.

Computation-Guided Design of a Stimulus-Responsive Multienzyme Supramolecular Assembly.

Science.gov (United States)

Yang, Lu; Dolan, Elliott M; Tan, Sophia K; Lin, Tianyun; Sontag, Eduardo D; Khare, Sagar D

2017-10-18

The construction of stimulus-responsive supramolecular complexes of metabolic pathway enzymes, inspired by natural multienzyme assemblies (metabolons), provides an attractive avenue for efficient and spatiotemporally controllable one-pot biotransformations. We have constructed a phosphorylation- and optically responsive metabolon for the biodegradation of the environmental pollutant 1,2,3-trichloropropane. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Anti-inflammatory polymersomes of redox-responsive polyprodrug amphiphiles with inflammation-triggered indomethacin release characteristics.

Science.gov (United States)

Tan, Jiajia; Deng, Zhengyu; Liu, Guhuan; Hu, Jinming; Liu, Shiyong

2018-03-21

Inflammation serves as a natural defense mechanism to protect living organisms from infectious diseases. Nonsteroidal anti-inflammatory drugs (NSAIDs) can help relieve inflammatory reactions and are clinically used to treat pain, fever, and inflammation, whereas long-term use of NSAIDs may lead to severe side effects including gastrointestinal damage and cardiovascular toxicity. Therefore, it is of increasing importance to configure new dosing strategies and alleviate the side effects of NSAIDs. Towards this goal, glutathione (GSH)-responsive disulfide bonds and hydrogen peroxide (H 2 O 2 )-reactive phenylboronic ester linkages were utilized as triggering moieties in this work to design redox-responsive prodrug monomers and polyprodrug amphiphiles based on indomethacin (IND) drug. Note that IND is a widely prescribed NSAID in the clinic. Starting from three types of redox-reactive IND prodrug monomers, redox-responsive polyprodrug amphiphiles were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerizations of prodrug monomers using poly(ethylene oxide) (PEO)-based macroRAFT agent. The resultant polyprodrug amphiphiles with high IND loading contents (>33 wt%) could self-assemble into polymersomes with PEO shielding coronas and redox-responsive bilayer membranes composed of IND prodrugs. Upon incubation with GSH or H 2 O 2 , controlled release of intact IND in the active form from polyprodrug polymersomes was actuated by GSH-mediated disulfide cleavage reaction and H 2 O 2 -mediated oxidation of phenylboronic ester moieties, respectively, followed by self-immolative degradation events. Furthermore, in vitro studies at the cellular level revealed that redox-responsive polymersomes could efficiently relieve inflammatory responses induced by lipopolysaccharide (LPS) in RAW264.7 macrophage cells. Copyright © 2018. Published by Elsevier Ltd.

Proteins evolve on the edge of supramolecular self-assembly

Science.gov (United States)

Garcia-Seisdedos, Hector; Empereur-Mot, Charly; Elad, Nadav; Levy, Emmanuel D.

2017-08-01

The self-association of proteins into symmetric complexes is ubiquitous in all kingdoms of life. Symmetric complexes possess unique geometric and functional properties, but their internal symmetry can pose a risk. In sickle-cell disease, the symmetry of haemoglobin exacerbates the effect of a mutation, triggering assembly into harmful fibrils. Here we examine the universality of this mechanism and its relation to protein structure geometry. We introduced point mutations solely designed to increase surface hydrophobicity among 12 distinct symmetric complexes from Escherichia coli. Notably, all responded by forming supramolecular assemblies in vitro, as well as in vivo upon heterologous expression in Saccharomyces cerevisiae. Remarkably, in four cases, micrometre-long fibrils formed in vivo in response to a single point mutation. Biophysical measurements and electron microscopy revealed that mutants self-assembled in their folded states and so were not amyloid-like. Structural examination of 73 mutants identified supramolecular assembly hot spots predictable by geometry. A subsequent structural analysis of 7,471 symmetric complexes showed that geometric hot spots were buffered chemically by hydrophilic residues, suggesting a mechanism preventing mis-assembly of these regions. Thus, point mutations can frequently trigger folded proteins to self-assemble into higher-order structures. This potential is counterbalanced by negative selection and can be exploited to design nanomaterials in living cells.

A Supramolecular Approach toward Bioinspired PAMAM-Dendronized Fusion Toxins.

Science.gov (United States)

Kuan, Seah Ling; Förtsch, Christina; Ng, David Yuen Wah; Fischer, Stephan; Tokura, Yu; Liu, Weina; Wu, Yuzhou; Koynov, Kaloian; Barth, Holger; Weil, Tanja

2016-06-01

Nature has provided a highly optimized toolbox in bacterial endotoxins with precise functions dictated by their clear structural division. Inspired by this streamlined design, a supramolecular approach capitalizing on the strong biomolecular (streptavidin (SA))-biotin interactions is reported herein to prepare two multipartite fusion constructs, which involves the generation 2.0 (D2) or generation 3.0 (D3) polyamidoamine-dendronized transporter proteins (dendronized streptavidin (D3SA) and dendronized human serum albumin (D2HSA)) non-covalently fused to the C3bot1 enzyme from Clostridium botulinum, a potent and specific Rho-inhibitor. The fusion constructs, D3SA-C3 and D2HSA-C3, represent the first examples of dendronized protein transporters that are fused to the C3 enzyme, and it is successfully demonstrated that the C3 Rho-inhibitor is delivered into the cytosol of mammalian cells as determined from the characteristic C3-mediated changes in cell morphology and confocal microscopy. The design circumvents the low uptake of the C3 enzyme by eukaryotic cells and holds great promise for reprogramming the properties of toxin enzymes using a supramolecular approach to broaden their therapeutic applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrodynamic and Thermophoretic Effects on the Supramolecular Chirality of Pyrene-Derived Nanosheets.

Science.gov (United States)

Micali, Norberto; Vybornyi, Mykhailo; Mineo, Placido; Khorev, Oleg; Häner, Robert; Villari, Valentina

2015-06-22

Chiroptical properties of two-dimensional (2D) supramolecular assemblies (nanosheets) of achiral, charged pyrene trimers (Py3 ) are rendered chiral by asymmetric physical perturbations. Chiral stimuli in a cuvette can originate either from controlled temperature gradients or by very gentle stirring. The chiroptical activity strongly depends on the degree of supramolecular order of the nanosheets, which is easily controlled by the method of preparation. The high degree of structural order ensures strong cooperative effects within the aggregates, rendering them more susceptible to external stimuli. The samples prepared by using slow thermal annealing protocols are both CD and LD active (in stagnant and stirred solutions), whereas for isothermally aged samples chiroptical activity was in all cases undetectable. In the case of temperature gradients, the optical activity of 2D assemblies could be recorded for a stagnant solution due to migration of the aggregates from the hottest to the coldest regions of the system. However, a considerably stronger exciton coupling, coinciding with the J-band of the interacting pyrenes, is developed upon subtle vortexing (0.5 Hz, 30 rpm) of the aqueous solution of the nanosheets. The sign of the exciton coupling is inverted upon switching between clockwise and counter-clockwise rotation. The supramolecular chirality is evidenced by the appearance of CD activity. To exclude artefacts from proper CD spectra, the contribution from LD to the observed CD was determined. The data suggest that the aggregates experience asymmetrical deformation and alignment effects because of the presence of chiral flows. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Self-assembled structures of amphiphilic ionic block copolymers: Theory, self-consistent field modeling and experiment

NARCIS (Netherlands)

Borisov, O.V.; Zhulina, E.B.; Leermakers, F.A.M.; Muller, A.H.E.

2011-01-01

We present an overview of statistical thermodynamic theories that describe the self-assembly of amphiphilic ionic/hydrophobic diblock copolymers in dilute solution. Block copolymers with both strongly and weakly dissociating (pH-sensitive) ionic blocks are considered. We focus mostly on structural

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.

Modulation of Cyclodextrin Particle Amphiphilic Properties to Stabilize Pickering Emulsion.

Science.gov (United States)

Xi, Yongkang; Luo, Zhigang; Lu, Xuanxuan; Peng, Xichun

2018-01-10

Cyclodextrins have been proven to form complexes with linear oil molecules and stabilize emulsions. Amphiphilic properties of cyclodextrin particles were modulated through esterification reaction between β-cyclodextrin (β-CD) and octadecenyl succinic anhydride (ODSA) under alkaline conditions. ODS-β-CD particles with degree of substitution (DS) of 0.003, 0.011, and 0.019 were obtained. The introduced hydrophobic long chain that was linked within β-CD cavity led to the change of ODS-β-CD in terms of morphological structure, surface charge density, size, and contact angle, upon which the properties and stability of the emulsions stabilized by ODS-β-CD were highly dependent. The average diameter of ODS-β-CD particles ranged from 449 to 1484 nm. With the DS increased from 0.003 to 0.019, the contact angle and absolute zeta potential value of these ODS-β-CD particles improved from 25.7° to 47.3° and 48.1 to 62.8 mV, respectively. The cage structure of β-CD crystals was transformed to channel structure, then further to amorphous structure after introduction of the octadecenyl succinylation chain. ODS-β-CD particles exhibited higher emulsifying ability compared to β-CD. The resulting Pickering emulsions formed by ODS-β-CD particles were more stable during storage. This study investigates the ability of these ODS-β-CD particles to stabilize oil-in-water emulsions with respect to their amphiphilic character and structural properties.

Artificial muscle-like function from hierarchical supramolecular assembly of photoresponsive molecular motors

NARCIS (Netherlands)

Chen, Jiawen; Leung, Franco King-Chi; Stuart, Marc C A; Kajitani, Takashi; Fukushima, Takanori; van der Giessen, Erik; Feringa, Ben L

A striking feature of living systems is their ability to produce motility by amplification of collective molecular motion from the nanoscale up to macroscopic dimensions. Some of nature's protein motors, such as myosin in muscle tissue, consist of a hierarchical supramolecular assembly of very large

Drastic symmetry breaking in supramolecular organization of enantiomerically unbalanced monolayers at surfaces

NARCIS (Netherlands)

Haq, S.; Liu, N.; Humblot, V.; Jansen, A.P.J.; Raval, R.

2009-01-01

There is considerable interest in skewing the transmission of chirality, or 'handedness', from the molecular to the supramolecular level so that single-handed superstructures are created from mixed enantiomer systems. One approach is to flip the chirality of all the molecular building blocks to the

Bio-inspired supramolecular materials by orthogonal self-assembly of hydrogelators and phospholipids

NARCIS (Netherlands)

Boekhoven, J.; Brizard, AMA; Stuart, M. C A; Florusse, L.J.; Raffy, G.; Del Guerzo, A.; van Esch, J.H.

2016-01-01

The orthogonal self-assembly of multiple components is a powerful strategy towards the formation of complex biomimetic architectures, but so far the rules for designing such systems are unclear. Here we show how to identify orthogonal self-assembly at the supramolecular level and describe

Supramolecular Ferric Porphyrins as Cyanide Receptors in Aqueous Solution

Science.gov (United States)

2011-01-01

All fundamental data about binding of the cyanide to a supramolecular complex composed of a per-O-methylated β-cyclodextrin dimer having an imidazole linker (Im3CD) and an anionic ferric porphyrin (Fe(III)TPPS) indicate that the Fe(III)TPPS/Im3CD complex is much better as an cyanide receptor in vivo than hydroxocobalamin, whose cyanide binding ability is lowered by its strong binding to serum proteins in the blood. PMID:24900285

A spectroscopic method to estimate the binding potency of amphiphile assemblies

Czech Academy of Sciences Publication Activity Database

Gauger, D. R.; Andrushchenko, Valery; Bouř, Petr; Pohle, W.

2010-01-01

Roč. 398, č. 2 (2010), s. 1109-1123 ISSN 1618-2642 R&D Projects: GA ČR GA203/06/0420; GA ČR GA202/07/0732; GA ČR GAP208/10/0559; GA AV ČR IAA400550702; GA AV ČR IAA400550701 Institutional research plan: CEZ:AV0Z40550506 Keywords : miccels * amphiphile assemblies * molecular dynamics * infrared spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.841, year: 2010

Metal-driven and covalent synthesis of supramolecular grids from racks: a convergent approach to heterometallic and heteroleptic nanostructures.

Science.gov (United States)

Schmittel, Michael; Kalsani, Venkateshwarlu; Bats, Jan W

2005-06-13

Supramolecular nanogrids were prepared from dynamic supramolecular racks through the coupling of terminal alkynes using either a covalent (with CuCl/O(2)) or a coordinative (with [trans-(PEt(3))(2)PtCl(2)]) approach. Because of the rapid equilibration of the racks (as tested by exchange reactions), oligomeric adducts potentially formed in the coupling process will selectively furnish the nanogrids through an entropically driven self-repair mechanism. To ascertain the structural assignment, the nanogrids were also synthesized by an independent strategy.

Effects of solubilization of short and medium-chain molecules in the self-assembly of two amphiphilic drugs in solution

International Nuclear Information System (INIS)

Barbosa, Silvia; Cheema, Mohammad Arif; Siddiq, Mohammad; Taboada, Pablo; Mosquera, Victor

2009-01-01

The effect of short and medium chain length alcohols ethanol, propanol, and butanol on the thermodynamic properties of aqueous solutions of the ionic amphiphilic antidepressants imipramine and clomipramine hydrochlorides has been investigated at T = 293 K. Critical concentrations of the drugs were obtained from ultrasound velocity measurements. Experimental results have shown a strong dependence of the ultrasound velocity with the alcohol concentration and chain length. Differences in the aggregate properties of both amphiphiles arise from the presence of the extra Cl - substituent on the ring system of clomipramine. Density and ultrasound measurements have been used to obtain the apparent molar volumes, V φ , and isentropic apparent molar compressibilities, K φ(S) , for the aqueous drug/water-alcohol solutions. The distribution coefficient of the amount solubilized between water and the aggregates, K, has been determined using an indirect method based on the pseudo-phase model by using apparent molar volume values. This method allows the calculation of the distribution coefficients at concentrations below saturation. The standard molar Gibbs free energy change on transfer from the aqueous to the micellar, ΔG 0 , phase was calculated from the partition coefficient. The results have highlighted the structural differences between both amphiphiles

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

Stable material modication with polymers incorporation for broad application in microfabrication

DEFF Research Database (Denmark)

Mednova, Olga

The aim of this thesis is to improve SU-8 fracture resistance in order to eliminate micro crack formation during fabrication of microelectromechanical system (MEMS). An amphiphilic block copolymer incorporation, as an efficient method of material toughening without changing its original properties...... analytical techniques. The second part of the thesis describes modified SU-8 blends. Thermal stability, structural organization, components interaction, hardness and brittleness of the composites are described. Finally, lithographic properties of modified SU-8 blends have been tested. Commercial SU-8...... and the modified blends demonstrate identically patternability and high aspect ratio structures can be obtained regardless of PEE-b-P2VP content. In conclusion, a recommendation of SU-8 modification with as little as 5 wt.% of PEE30-b-P2VP69 is made in order to avoid micro crack formation and its growth during...

Growth anomalies in supramolecular networks: 4,4'-biphenyldicarboxylic acid on Cu(001)

NARCIS (Netherlands)

Schwarz, Daniel; van Gastel, Raoul; Zandvliet, Henricus J.W.; Poelsema, Bene

2013-01-01

We have used low energy electron microscopy to demonstrate how the interaction of 4,4 ′ -biphenyldicarboxylic acid (BDA) molecules with (steps on) the Cu(001) surface determines the structure of supramolecular BDA networks on a mesoscopic length scale. Our in situ real time observations reveal that

Supramolecular Chirality: Solvent Chirality Transfer in Molecular Chemistry and Polymer Chemistry

Directory of Open Access Journals (Sweden)

Michiya Fujiki

2014-08-01

Full Text Available Controlled mirror symmetry breaking arising from chemical and physical origin is currently one of the hottest issues in the field of supramolecular chirality. The dynamic twisting abilities of solvent molecules are often ignored and unknown, although the targeted molecules and polymers in a fluid solution are surrounded by solvent molecules. We should pay more attention to the facts that mostly all of the chemical and physical properties of these molecules and polymers in the ground and photoexcited states are significantly influenced by the surrounding solvent molecules with much conformational freedom through non-covalent supramolecular interactions between these substances and solvent molecules. This review highlights a series of studies that include: (i historical background, covering chiral NaClO3 crystallization in the presence of d-sugars in the late 19th century; (ii early solvent chirality effects for optically inactive chromophores/fluorophores in the 1960s–1980s; and (iii the recent development of mirror symmetry breaking from the corresponding achiral or optically inactive molecules and polymers with the help of molecular chirality as the solvent use quantity.

Enhancing SERS by Means of Supramolecular Charge Transfer

Science.gov (United States)

Wong, Eric; Flood, Amar; Morales, Alfredo

2009-01-01

In a proposed method of sensing small quantities of molecules of interest, surface enhanced Raman scattering (SERS) spectroscopy would be further enhanced by means of intermolecular or supramolecular charge transfer. There is a very large potential market for sensors based on this method for rapid detection of chemical and biological hazards. In SERS, the Raman signals (vibrational spectra) of target molecules become enhanced by factors of the order of 108 when those molecules are in the vicinities of nanostructured substrate surfaces that have been engineered to have plasmon resonances that enhance local electric fields. SERS, as reported in several prior NASA Tech Briefs articles and elsewhere, has remained a research tool and has not yet been developed into a practical technique for sensing of target molecules: this is because the short range (5 to 20 nm) of the field enhancement necessitates engineering of receptor molecules to attract target molecules to the nanostructured substrate surfaces and to enable reliable identification of the target molecules in the presence of interferants. Intermolecular charge-transfer complexes have been used in fluorescence-, photoluminescence-, and electrochemistry-based techniques for sensing target molecules, but, until now, have not been considered for use in SERS-based sensing. The basic idea of the proposed method is to engineer receptor molecules that would be attached to nanostructured SERS substrates and that would interact with the target molecules to form receptor-target supramolecular charge-transfer complexes wherein the charge transfer could be photoexcited.

Synthesis and Crystal Structure of an Unprecedented Supramolecular Complex[Co(μ2-ClO4)2(H2O)2]·2MA

Institute of Scientific and Technical Information of China (English)

XU,Jing; BAI,Zhengshuai; SUN,Weiyin

2009-01-01

A new supramolecular framework[Co(μ2-C104)2(H2O)2]·2MA(1)[MA=melamine(C3H6N6)]has been syn-thesized by a hydrothermal method.Interestingly,there ale inorganic and organic building blocks with two different supramolecular synthons:(a)2D(4,4)network constructed by infinite inorganic 1D chains through interchain hy-drogen bonding interactions;(b)1D zigzag organic chains formed by hydrogen bonds, which further stack up through,ππ-interactions between the two adjacent MA molecules.The entire structure of 1 is a 3D supramolecular framework resulting from the presence of abundant hydrogen bonds between infinite[CO(μ2-C1O4)2(H2O)2]n chains and zigzag MA chains in different sheets.1 gives a nice example of supramolecular framework based on non-covalent interactions including hydrogen bonding and π-π interactions.

Supramolecular assembly affording a ratiometric two-photon fluorescent nanoprobe for quantitative detection and bioimaging.

Science.gov (United States)

Wang, Peng; Zhang, Cheng; Liu, Hong-Wen; Xiong, Mengyi; Yin, Sheng-Yan; Yang, Yue; Hu, Xiao-Xiao; Yin, Xia; Zhang, Xiao-Bing; Tan, Weihong

2017-12-01

Fluorescence quantitative analyses for vital biomolecules are in great demand in biomedical science owing to their unique detection advantages with rapid, sensitive, non-damaging and specific identification. However, available fluorescence strategies for quantitative detection are usually hard to design and achieve. Inspired by supramolecular chemistry, a two-photon-excited fluorescent supramolecular nanoplatform ( TPSNP ) was designed for quantitative analysis with three parts: host molecules (β-CD polymers), a guest fluorophore of sensing probes (Np-Ad) and a guest internal reference (NpRh-Ad). In this strategy, the TPSNP possesses the merits of (i) improved water-solubility and biocompatibility; (ii) increased tissue penetration depth for bioimaging by two-photon excitation; (iii) quantitative and tunable assembly of functional guest molecules to obtain optimized detection conditions; (iv) a common approach to avoid the limitation of complicated design by adjustment of sensing probes; and (v) accurate quantitative analysis by virtue of reference molecules. As a proof-of-concept, we utilized the two-photon fluorescent probe NHS-Ad-based TPSNP-1 to realize accurate quantitative analysis of hydrogen sulfide (H 2 S), with high sensitivity and good selectivity in live cells, deep tissues and ex vivo -dissected organs, suggesting that the TPSNP is an ideal quantitative indicator for clinical samples. What's more, TPSNP will pave the way for designing and preparing advanced supramolecular sensors for biosensing and biomedicine.

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.

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......-stacking and two-dimensional branched nanobuds through H-stacking. Graphene integrated supramolecular nanocomposites are highly stable and show significant enhancement of photocurrent generation in these two configurations of photosensing devices, i.e. solid-state optoelectronic constructs and liquid...

Repurposing Cationic Amphiphilic Antihistamines for Cancer Treatment

DEFF Research Database (Denmark)

Ellegaard, Anne-Marie; Dehlendorff, Christian; Vind, Anna C.

2016-01-01

Non-small cell lung cancer (NSCLC) is one of the deadliest cancers worldwide. In search for new NSCLC treatment options, we screened a cationic amphiphilic drug (CAD) library for cytotoxicity against NSCLC cells and identified several CAD antihistamines as inducers of lysosomal cell death. We...... then performed a cohort study on the effect of CAD antihistamine use on mortality of patients diagnosed with non-localized cancer in Denmark between 1995 and 2011. The use of the most commonly prescribed CAD antihistamine, loratadine, was associated with significantly reduced all-cause mortality among patients...... with non-localized NSCLC or any non-localized cancer when compared with use of non-CAD antihistamines and adjusted for potential confounders. Of the less frequently described CAD antihistamines, astemizole showed a similar significant association with reduced mortality as loratadine among patients with any...

Supramolecular binding and release of sulfide and hydrosulfide anions in water.

Science.gov (United States)

Vázquez, J; Sindelar, V

2018-06-05

Hydrogen sulfide (H2S) has become an important target for research due to its physiological properties as well as its potential applications in medicine. In this work, supramolecular binding of sulfide (S2-) and hydrosulfide (HS-) anions in water is presented for the first time. Bambusurils were used to slow down the release of these anions in water.

Cucurbit[8]uril templated supramolecular ring structure formation and protein assembly modulation

NARCIS (Netherlands)

Ramaekers, M.; Wijnands, S.P.W.; van Dongen, J.L.J.; Brunsveld, L.; Dankers, P.Y.W.

2015-01-01

The interplay of Phe-Gly-Gly (FGG)-tagged proteins and bivalent FGG-tagged penta(ethylene glycol) as guest molecules with cucurbit[8]uril (Q8) hosts is studied to modulate the supramolecular assembly process. Ring structure formation of the bivalent guest molecule with Q8 leads to enhanced binding

Amphiphilic derivatives of (3β,17β)-3-hydroxyandrost-5-ene-17-carboxylic acid

Czech Academy of Sciences Publication Activity Database

Özdemir, Zülal; Bildziukevich, Uladzimir; Šaman, David; Havlíček, Libor; Rárová, L.; Navrátilová, L.; Wimmer, Zdeněk

2017-01-01

Roč. 128, DEC (2017), s. 58-67 ISSN 0039-128X R&D Projects: GA MŠk LD15012 Institutional support: RVO:61389030 ; RVO:61388963 Keywords : Amphiphile * Antimicrobial activity * Cytotoxicity * Diamine * Polyamine * Steroid Subject RIV: CC - Organic Chemistry; CC - Organic Chemistry (UOCHB-X) OBOR OECD: Organic chemistry Impact factor: 2.282, year: 2016

Dynamic stability of nano-fibers self-assembled from short amphiphilic A6D peptides.

Science.gov (United States)

Nikoofard, Narges; Maghsoodi, Fahimeh

2018-04-07

Self-assembly of A 6 D amphiphilic peptides in explicit water is studied by using coarse-grained molecular dynamics simulations. It is observed that the self-assembly of randomly distributed A 6 D peptides leads to the formation of a network of nano-fibers. Two other simulations with cylindrical nano-fibers as the initial configuration show the dynamic stability of the self-assembled nano-fibers. As a striking feature, notable fluctuations occur along the axes of the nano-fibers. Depending on the number of peptides per unit length of the nano-fiber, flat-shaped bulges or spiral shapes along the nano-fiber axis are observed at the fluctuations. Analysis of the particle distribution around the nano-fiber indicates that the hydrophobic core and the hydrophilic shell of the nano-structure are preserved in both simulations. The size of the deformations and their correlation times are different in the two simulations. This study gives new insights into the dynamics of the self-assembled nano-structures of short amphiphilic peptides.

Dynamic stability of nano-fibers self-assembled from short amphiphilic A6D peptides

Science.gov (United States)

Nikoofard, Narges; Maghsoodi, Fahimeh

2018-04-01

Self-assembly of A6D amphiphilic peptides in explicit water is studied by using coarse-grained molecular dynamics simulations. It is observed that the self-assembly of randomly distributed A6D peptides leads to the formation of a network of nano-fibers. Two other simulations with cylindrical nano-fibers as the initial configuration show the dynamic stability of the self-assembled nano-fibers. As a striking feature, notable fluctuations occur along the axes of the nano-fibers. Depending on the number of peptides per unit length of the nano-fiber, flat-shaped bulges or spiral shapes along the nano-fiber axis are observed at the fluctuations. Analysis of the particle distribution around the nano-fiber indicates that the hydrophobic core and the hydrophilic shell of the nano-structure are preserved in both simulations. The size of the deformations and their correlation times are different in the two simulations. This study gives new insights into the dynamics of the self-assembled nano-structures of short amphiphilic peptides.

Sodium effect on self-organization of amphiphilic carboxylates: formation of structured micelles and superlattices.

Science.gov (United States)

Rosenlehner, Karin; Schade, Boris; Böttcher, Christoph; Jäger, Christof M; Clark, Timothy; Heinemann, Frank W; Hirsch, Andreas

2010-08-16

Not only the self-aggregation of dendritic polycarboxylates into structurally persistent micelles, but also that of the micelles themselves into superlattices is controlled by alkali-metal counterions and shows a pronounced sodium effect. Our combined experimental and computational work has revealed the formation of superlattices for the first time. The behavior of a variety of amphiphilic carboxylates and the different effects of the alkali cations Li(+), Na(+), and K(+) have been investigated by conductivity measurements, cryogenic transmission electron microscopy (cryo-TEM), and molecular-dynamics (MD) simulations. Together, these show that sodium salts of the amphiphiles give the most stable micelles, followed by lithium and potassium. Our results suggest that ion multiplets in bridging positions, rather than contact ion pairs, are responsible for the enhanced stability and the formation of hexagonally ordered superlattices with sodium counterions. Potassium ions do not form such ion multiplets and cannot therefore induce aggregation of the micelles. This sodium effect has far-reaching consequences for a large number of biological and technical systems and sheds new light on the origin of specific-ion effects.

Incorporation of amphiphilic ruthenium(II) ammine complexes into Langmuir-Blodgett thin films with switchable quadratic nonlinear optical behavior.

Science.gov (United States)

Boubekeur-Lecaque, Leïla; Coe, Benjamin J; Harris, James A; Helliwell, Madeleine; Asselberghs, Inge; Clays, Koen; Foerier, Stijn; Verbiest, Thierry

2011-12-19

Nine nonlinear optical (NLO) chromophores with pyridinium electron acceptors have been synthesized by complexing new proligands with {Ru(II)(NH(3))(5)}(2+) electron-donor centers. The presence of long alkyl/fluoroalkyl chain substituents imparts amphiphilic properties, and these cationic complexes have been characterized as their PF(6)(-) salts by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Each complex shows three reversible/quasireversible redox processes; a Ru(III/II) oxidation and two ligand-based reductions. The energies of the intense visible d → π* metal-to-ligand charge-transfer (MLCT) absorptions correlate to some extent with the ligand reduction potentials. (1)H NMR spectroscopy also provides insights into the relative electron-withdrawing strengths of the new ligands. Single crystal X-ray structures have been determined for two of the proligand salts and one complex salt, [Ru(II)(NH(3))(5)(4-C(16)H(33)PhQ(+))]Cl(3)·3.25H(2)O (PhQ(+) = N-phenyl-4,4'-bipyridinium), showing centrosymmetric packing structures in each case. The PF(6)(-) analogue of the latter complex has been used to deposit reproducibly high-quality, multilayered Langmuir-Blodgett (LB) thin films. These films show a strong second harmonic generation (SHG) response from a 1064 nm laser; their MLCT absorbance increases linearly with the number of layers (N) and I(2ω)/I(ω)(2) (I(2ω) = intensity at 532 nm; I(ω) = intensity at 1064 nm) scales quadratically with N, consistent with homogeneous deposition. LB films on indium tin oxide (ITO)-coated glass show electrochemically induced switching of the SHG response, with a decrease in activity of about 50% on Ru(II) → Ru(III) oxidation. This effect is reversible, but reproducible over only a few cycles before the signal from the Ru(II) species diminishes. This work extrapolates our original solution studies (Coe, B. J. et al. Angew. Chem., Int. Ed.1999, 38, 366) to the first demonstration of

Electrochemical supramolecular recognition of hemin-carbon composites

Science.gov (United States)

Le, Hien Thi Ngoc; Jeong, Hae Kyung

2018-04-01

Hemin-graphite oxide-carbon nanotube (hemin-GO-CNT) and hemin-thermally reduced graphite oxide-carbon nanotube (hemin-TRGO-CNT) composites are synthesized and investigated for the electrochemical supramolecular recognition by electron transfer between biomolecules (dopamine and hydrogen peroxide) and the composite electrodes. Redox reaction mechanisms of two composites with dopamine and hydrogen peroxide are explained in detail by using cyclic voltammetry and differential pulse voltammetry. Hemin-TRGO-CNT displays higher electrochemical detection for dopamine and hydrogen peroxide than that of hemin-GO-CNT, exhibiting enhancement of the electron transfer due to the effective immobilization of redox couple of hemin (Fe2+/Fe3+) on the TRGO-CNT surface.

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

Syntheses and structures of three supramolecular complexes based on 2-(pyridine-2-yl)-1H-imidazole-4,5-dicarboxylic acid

Science.gov (United States)

Yu, Xiao-Yang; Zhang, Xiao; Liu, Zhi-Gang; Cui, Xiao-Bing; Xu, Jia-Ning; Luo, Yu-Hui

2017-11-01

Three new supramolecular compounds, [Cu(o-HPIDC)(bpy)(H2O)]·2H2O 1, [Cu(o-H2PIDC)(phen)Cl]·[Cu(phen)2Cl]·10H2O·Cl 2 and {[Cd(o-H2PIDC)(H2O)2Cl]·H2O}23 (o-H3PIDC = 2-(pyridine-2-yl)-1H-imidazole-4,5-dicarboxylic acid, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline), were hydrothermally synthesized and characterized. In compound 1, the adjacent two supramolecular layers are constructed from different types of helical chains with the same pitch. In compound 2, the adjacent 2D water-chloride layers, {[(H2O)10Cl]-}n, are pillared by [Cu(o-H2PIDC)(phen)Cl] units to form the overall 3D supramolecular network with 1D channels through Osbnd H⋯O hydrogen bond interactions. In compound 3, two Cd(II) are linked into a binuclear [Cd2(o-H2PIDC)2(H2O)4Cl2] with a ten-membered ring by two o-H2PIDC- ligands. The three compounds self-assemble into 3D supramolecular structures via hydrogen bond and π-π stacking interactions. The fluorescence properties of compound 3 was also investigated.

Functional organic materials based on polymerized liquid-crystal monomers: supramolecular hydrogen-bonded systems

NARCIS (Netherlands)

Broer, D.J.; Bastiaansen, C.W.M.; Debije, M.G.; Schenning, A.P.H.J.

2012-01-01

Functional organic materials are of great interest for a variety of applications. To obtain precise functional properties, well-defined hierarchically ordered supramolecular materials are crucial. The self-assembly of liquid crystals has proven to be an extremely useful tool in the development of

Supramolecular Control of Oligothienylenevinylene-Fullerene Interactions: Evidence for a Ground-State EDA Complex

NARCIS (Netherlands)

McClenaghan, N.D.; Grote, Z.; Darriet, K.; Zimine, M.Y.; Williams, R.M.; De Cola, L.; Bassani, D.M.

2005-01-01

Complementary hydrogen-bonding interactions between a barbituric acid-substituted fullerene derivative (1) and corresponding receptor (2) bearing thienylenevinylene units are used to assemble a 1:1 supramolecular complex ( K ) 5500 M-1). Due to the close proximity of the redox-active moieties within

Amphiphilic poly(ether ester amide) multiblock copolymers as biodegradable matrices for the controlled release of proteins

NARCIS (Netherlands)

Bezemer, J.M.; Oude Weme, P.; Grijpma, Dirk W.; Dijkstra, Pieter J.; van Blitterswijk, Clemens; Feijen, Jan

2000-01-01

Amphiphilic poly(ether ester amide) (PEEA) multiblock copolymers were synthesized by polycondensation in the melt from hydrophilic poly(ethylene glycol) (PEG), 1,4-dihydroxybutane and short bisester-bisamide blocks. These amide blocks were prepared by reaction of 1,4-diaminobutane with dimethyl

Immobilization of ferrocene-modified SNAP-fusion proteins

NARCIS (Netherlands)

Wasserberg, D.; Uhlenheuer, D.; Neirynck, P.; Neirynck, Pauline; Cabanas Danés, Jordi; Schenkel, J.H.; Ravoo, B.J.; An, Q.; Huskens, Jurriaan; Milroy, L.G.; Brunsveld, Luc; Jonkheijm, Pascal

2013-01-01

The supramolecular assembly of proteins on surfaces has been investigated via the site-selective incorporation of a supramolecular moiety on proteins. To this end, fluorescent proteins have been site-selectively labeled with ferrocenes, as supramolecular guest moieties, via SNAP-tag technology. The

Synthesis and characterization of metallo-supramolecular polymers from thiophene-based unimers bearing pybox ligands

Czech Academy of Sciences Publication Activity Database

Hladysh, S.; Václavková, D.; Vrbata, D.; Bondarev, D.; Havlíček, D.; Svoboda, Jan; Zedník, J.; Vohlídal, J.

2017-01-01

Roč. 7, č. 18 (2017), s. 10718-10728 ISSN 2046-2069 Institutional support: RVO:61389013 Keywords : metallo-supramolecular polymers * XPS Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.108, year: 2016

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......-adsorbed to DDA:MMG-1/3/6 dispersions revealed that all tested adjuvants were immunoactive and induced strong Th1 and Th17 responses with a potential for a central effector memory profile. The MMG-1 and MMG-6 analogues were equally immunoactive in vivo upon incorporation into DDA liposomes, despite the reported...

Gd-DTPA-Dopamine-Bisphytanyl Amphiphile: Synthesis, Characterisation and Relaxation Parameters of the Nanoassemblies and Their Potential as MRI Contrast Agents.

Science.gov (United States)

Gupta, Abhishek; Willis, Scott A; Waddington, Lynne J; Stait-Gardner, Tim; de Campo, Liliana; Hwang, Dennis W; Kirby, Nigel; Price, William S; Moghaddam, Minoo J

2015-09-28

Here, a new amphiphilic magnetic resonance imaging (MRI) contrast agent, a Gd(III)-chelated diethylenetriaminepentaacetic acid conjugated to two branched alkyl chains via a dopamine spacer, Gd-DTPA-dopamine-bisphytanyl (Gd-DTPA-Dop-Phy), which is readily capable of self-assembling into liposomal nanoassemblies upon dispersion in an aqueous solution, is reported. In vitro relaxivities of the dispersions were found to be much higher than Magnevist, a commercially available contrast agent, at 0.47 T but comparable at 9.40 T. Analysis of variable temperature (17)O NMR transverse relaxation measurements revealed the water exchange of the nanoassemblies to be faster than that previously reported for paramagnetic liposomes. Molecular reorientation dynamics were probed by (1)H NMRD profiles using a classical inner and outer sphere relaxation model and a Lipari-Szabo "model-free" approach. High payloads of Gd(III) ions in the liposomal nanoassemblies made solely from the Gd-DTPA-Dop-Phy amphiphiles, in combination with slow molecular reorientation and fast water exchange makes this novel amphiphile a suitable candidate to be investigated as an advanced MRI contrast agent. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular organisation of oligo(p-phenylenevinylene) at the air-water interface and in water

NARCIS (Netherlands)

Jonkheijm, P.; Fransen, M.; Schenning, A.P.H.J.; Meijer, E.W.

2001-01-01

Two novel chiral (bola)amphiphilic oligo(p-phenylenevinylene)s (OPVs) have been synthesised and fully characterised. Decoration of the hydrophobic OPV backbone with a hydrophilic tris[tetra(ethylene oxide)]benzene wedge on one side and a hydrophobic tris(alkoxy)benzene wedge on the other side,

Carborane-beta-cyclodextrin complexes as a supramolecular connector for bioactive surfaces

Czech Academy of Sciences Publication Activity Database

Neirynck, P.; Schimer, Jiří; Jonkheijm, P.; Milroy, L. G.; Cígler, Petr; Brunsveld, L.

2015-01-01

Roč. 3, č. 4 (2015), s. 539-545 ISSN 2050-750X R&D Projects: GA MŠk(CZ) LH11027 Institutional support: RVO:61388963 Keywords : beta-cyclodextrine/carborane host-guest system * supramolecular chemistry * bioactive surfaces Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.872, year: 2015 http://pubs.rsc.org/en/content/articlepdf/2015/tb/c4tb01489h

Understanding the molecular mechanisms involved in the interfacial self-healing of supramolecular rubbers

NARCIS (Netherlands)

Bose, R.K.; Garcia Espallargas, S.J.; Van der Zwaag, S.

2013-01-01

Supramolecular rubbers based on 2-aminoethylimidazolidone and fatty acids with epoxy crosslinks have been shown to self-heal via multiple hydrogen bonding sites. In this work, several tools are used to investigate the molecular mechanisms taking place at the interface to understand cohesive healing

Microfluidic Droplet-Facilitated Hierarchical Assembly for Dual Cargo Loading and Synergistic Delivery.

Science.gov (United States)

Yu, Ziyi; Zheng, Yu; Parker, Richard M; Lan, Yang; Wu, Yuchao; Coulston, Roger J; Zhang, Jing; Scherman, Oren A; Abell, Chris

2016-04-06

Bottom-up hierarchical assembly has emerged as an elaborate and energy-efficient strategy for the fabrication of smart materials. Herein, we present a hierarchical assembly process, whereby linear amphiphilic block copolymers are self-assembled into micelles, which in turn are accommodated at the interface of microfluidic droplets via cucurbit[8]uril-mediated host-guest chemistry to form supramolecular microcapsules. The monodisperse microcapsules can be used for simultaneous carriage of both organic (Nile Red) and aqueous-soluble (fluorescein isothiocyanate-dextran) cargo. Furthermore, the well-defined compartmentalized structure benefits from the dynamic nature of the supramolecular interaction and offers synergistic delivery of cargos with triggered release or through photocontrolled porosity. This demonstration of premeditated hierarchical assembly, where interactions from the molecular to microscale are designed, illustrates the power of this route toward accessing the next generation of functional materials and encapsulation strategies.

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.

D-amino acid-containing supramolecular nanofibers for potential cancer therapeutics.

Science.gov (United States)

Wang, Huaimin; Feng, Zhaoqianqi; Xu, Bing

2017-02-01

Nanostructures formed by peptides that self-assemble in water through non-covalent interactions have attracted considerable attention because peptides possess several unique advantages, such as modular design and easiness of synthesis, convenient modification with known functional motifs, good biocompatibility, low immunogenicity and toxicity, inherent biodegradability, and fast responses to a wide range of external stimuli. After about two decades of development, peptide-based supramolecular nanostructures have already shown great potentials in the fields of biomedicine. Among a range of biomedical applications, using such nanostructures for cancer therapy has attracted increased interests since cancer remains the major threat for human health. Comparing with L-peptides, nanostructures containing peptides made of D-amino acid (i.e., D-peptides) bear a unique advantage, biostability (i.e., resistance towards most of endogenous enzymes). The exploration of nanostructures containing D-amino acids, especially their biomedical applications, is still in its infancy. Herein we review the recent progress of D-amino acid-containing supramolecular nanofibers as an emerging class of biomaterials that exhibit unique features for the development of cancer therapeutics. In addition, we give a brief perspective about the challenges and promises in this research direction. Copyright © 2016 Elsevier B.V. All rights reserved.

Amphiphilic invertible polymers: Self-assembly into functional materials driven by environment polarity

Science.gov (United States)

Hevus, Ivan

Stimuli-responsive polymers adapt to environmental changes by adjusting their chain conformation in a fast and reversible way. Responsive polymeric materials have already found use in electronics, coatings industry, personal care, and bio-related areas. The current work aims at the development of novel responsive functional polymeric materials by manipulating environment-dependent self-assembly of a new class of responsive macromolecules strategically designed in this study,—amphiphilic invertible polymers (AIPs). Environment-dependent micellization and self-assembly of three different synthesized AIP types based on poly(ethylene glycol) as a hydrophilic fragment and varying hydrophobic constituents was demonstrated in polar and nonpolar solvents, as well as on the surfaces and interfaces. With increasing concentration, AIP micelles self-assemble into invertible micellar assemblies composed of hydrophilic and hydrophobic domains. Polarity-responsive properties of AIPs make invertible micellar assemblies functional in polar and nonpolar media including at interfaces. Thus, invertible micellar assemblies solubilize poorly soluble substances in their interior in polar and nonpolar solvents. In a polar aqueous medium, a novel stimuli-responsive mechanism of drug release based on response of AIP-based drug delivery system to polarity change upon contact with the target cell has been established using invertible micellar assemblies loaded with curcumin, a phytochemical drug. In a nonpolar medium, invertible micellar assemblies were applied simultaneously as nanoreactors and stabilizers for size-controlled synthesis of silver nanoparticles stable in both polar and nonpolar media. The developed amphiphilic nanosilver was subsequently used as seeds to promote anisotropic growth of CdSe semiconductor nanoparticles that have potential in different applications ranging from physics to medicine. Amphiphilic invertible polymers were shown to adsorb on the surface of silica

Supramolecular polyaniline hydrogel as a support for urease

International Nuclear Information System (INIS)

Słoniewska, Anna; Pałys, Barbara

2014-01-01

Supramolecular hydrogels of conducting polymers are successfully used in bioelectrochemistry because of their mechanical and swelling properties of gels added to the specific electron transport properties of conducting polymers. We have studied polyaniline-poly(styrene sulfonate) (PANI–PSS) hydrogel as a substrate for the urease. The hydrogels were synthesized at pH = 0 and pH = 5. PANI–PSS hydrogel is a supramolecular self-assembly material consisting of positively-charged PANI chains and negatively-charged PSS chains. The hydrogel was studied by cyclic voltammetry, infrared and Raman spectroscopy and Scanning Electron Microscopy (SEM). Raman spectra revealed presence of phenazine rings in the hydrogel structure. Phenazine rings form covalent cross-linkers contributing to the hydrogel mechanical stability. The covalent cross-linkers influence the cyclic voltammetry responses of the hydrogel in acidic media. We tested the activity of urease immobilized in the PANI–PSS hydrogel by the physical adsorption or by the covalent bonding with the carbodiimide reaction. The enzyme immobilized in hydrogels prepared at higher pH value reveals significantly higher sensitivity. The method of the enzyme immobilization has smaller impact on the sensitivity. All hydrogel sensors reveal largely higher sensitivity to urea comparing to urease immobilized in the typical electrochemically deposited PANI films. The sensitivity of urease covalently bond to the hydrogel obtained at pH = 5 was as high as 1693 μA/(mol dm 3 ). The sensor response was linear in the urea concentration range from 10 −4 to 7 × 10 −2 mol/dm 3

Hydrophobic cotton textile surfaces using an amphiphilic graphene oxide (GO) coating

International Nuclear Information System (INIS)

Tissera, Nadeeka D.; Wijesena, Ruchira N.; Perera, J. Rangana; Nalin de Silva, K.M.; Amaratunge, Gehan A.J.

2015-01-01

Graphical abstract: - Highlights: • Different GO dispersions were prepared by sonicating different amounts of GO in water. Degree of exfoliation of these GO sheets in water was analyzed using Atomic Force Microscopy (AFM). • AFM results obtained showed higher the GO concentration on water more the size of GO sheets and lesser the degree of exfoliation. • GO with different amounts was deposited on cotton fabric using simple dyeing method. • High GO loading on cotton increase the surface area coverage of the textile fibers with GO sheets. This led to less edge to mid area ratio of grafted GO sheets. • As contribution of mid area of GO increase on fiber surface cotton fabric becomes more hydrophobic. • Amphiphilic property of GO sheets was used to lower the surface energy of the cotton fibers leading to hydrophobic property. - Abstract: We report for the first time hydrophobic properties on cotton fabric successfully achieved by grafting graphene oxide on the fabric surface, using a dyeing method. Graphite oxide synthesized by oxidizing natural flake graphite employing improved Hummer's method showed an inter layer spacing of ∼1 nm from XRD. Synthesized graphite oxide was exfoliated in water using ultrasound energy to obtain graphene oxide (GO). AFM data obtained for the graphene oxide dispersed in an aqueous medium revealed a non-uniform size distribution. FTIR characterization of the synthesized GO sheets showed both hydrophilic and hydrophobic functional groups present on the nano sheets giving them an amphiphilic property. GO flakes of different sizes were successfully grafted on to a cotton fabric surface using a dip dry method. Loading different amounts of graphene oxide on the cotton fiber surface allowed the fabric to demonstrate different degrees of hydrophobicity. The highest observed water contact angle was at 143° with the highest loading of graphene oxide. The fabric surfaces grafted with GO also exhibits adhesive type hydrophobicity

Supramolecular structure of a perylene derivative in thin films deposited by physical vapor deposition

International Nuclear Information System (INIS)

Fernandes, Jose D.; Aoki, Pedro H.B.; Constantino, Carlos J.J.; Junior, Wagner D.M.; Teixeira, Silvio R.

2014-01-01

Full text: Thin films of a perylene derivative, the bis butylimido perylene (BuPTCD), were produced using thermal evaporation (PVD, physical vapor deposition). The main objective is to investigate the supramolecular structure of the BuPTCD in these PVD films, which implies to control the thickness and to determine the molecular organization, morphology at micro and nanometer scales and crystallinity. This supramolecular structure is a key factor in the optical and electrical properties of the film. The ultraviolet-visible absorption revealed an uniform growth of the PVD films. The optical and atomic force microscopy images showed a homogeneous surface of the film at micro and nanometer scales. A preferential orientation of the molecules in the PVD films was determined via infrared absorption. The X-ray diffraction showed that both powder and PVD film are in the crystalline form. (author)

Supramolecular structure of jackfruit seed starch and its relationship with digestibility and physicochemical properties.

Science.gov (United States)

Chen, Jin; Liang, Yi; Li, Xiaoxi; Chen, Ling; Xie, Fengwei

2016-10-05

The influence of supramolecular structure on the physicochemical properties and digestibility of jackfruit seed starch (JSS) were investigated. Compared with maize and cassava starches (MS and CS), JSS had smaller granules and higher amylose content (JSS: 24.90%; CS: 16.68%; and MS: 22.42%), which contributed to higher gelatinization temperature (To: 81.11°C) and setback viscosity (548.9mPas). From scanning electron microscopy, the digestion of JSS was observed mainly at the granule surface. Due to its higher crystallinity (JSS: 30.6%; CS: 30.3%; and MS: 27.4%) and more ordered semi-crystalline lamellae, JSS had a high RS content (74.26%) and melting enthalpy (19.61J/g). In other words, the supramolecular structure of JSS extensively determined its digestibility and resistance to heat and mechanical shear treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

KAUST Repository

Zhu, Yutian

2012-01-01

In the current study, we applied the Monte Carlo method to study the self-assembly of linear ABC amphiphiles composed of two solvophobic A and B blocks and a solvophilic C block. A great number of multicompartment micelles are discovered from the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between the different block types. When the B block is longer than or as same as the terminal A block, a rich variety of micellar structures can be formed from ABC amphiphiles. By adjusting the solvent quality or incompatibility between the different block types, multiple morphological transitions are observed. These morphological sequences are well explained and consistent with all the previous experimental and theoretical studies. Despite the complexity of the micellar structures and morphological transitions observed for the self-assembly of ABC amphiphiles, two important common features of the phase behavior are obtained. In general, the micellar structures obtained in the current study can be divided into zero-dimensional (sphere-like structures, including bumpy-surfaced spheres and sphere-on-sphere structures), one-dimensional (cylinder-like structures, including rod and ring structures), two-dimensional (layer-like structures, including disk, lamella and worm-like and hamburger structures) and three-dimensional (vesicle) structures. It is found that the micellar structures transform from low- to high- dimensional structures when the solvent quality for the solvophobic blocks is decreased. In contrast, the micellar structures transform from high- to low-dimensional structures as the incompatibility between different block types increases. Furthermore, several novel micellar structures, such as the CBABC five-layer vesicle, hamburger, CBA three-layer ring, wormlike shape with

Organização supramolecular da ftalocianina de cobalto(II e seu efeito na oxidação do aminoácido cisteína Supramolecular organization of cobalt (II phthalocyanine on the pathway of cysteine oxidation

Directory of Open Access Journals (Sweden)

Amanda Costa Santos

2010-01-01

Full Text Available The interest in the chemistry of cobalt (II tetrasulfonated phthalocyanine (PcTsCo comes mainly from its macrocycle-ligand structure combined with their special chemical characteristics, such as high solubility, well-defined redox reactions and remarkable optical absorption in the visible region. In this work, we use layer-by-layer technique in order to assemble CoTsPc and poly(allylaminehydrochloride (PAH in hybrid supramolecular system. The electronic spectroscopy and cyclic voltammetry techniques were utilized to study PAH/CoTsPc multilayers growth and the cysteine catalytic oxidation. PAH/CoTsPc showed high electrochemical stability and worthwhile to mention is the remarkable influence of supramolecular arrangement on the final redox properties of the system.

On the kinetics of body versus end evaporation and addition of supramolecular polymers

NARCIS (Netherlands)

Tiwari, Nitin S.; van der Schoot, Paul

2017-01-01

Abstract.: The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling

On the kinetics of body versus end evaporation and addition of supramolecular polymers

NARCIS (Netherlands)

Tiwari, N.; van der Schoot, P.P.A.M.

2017-01-01

The kinetics of the self-assembly of supramolecular polymers is dictated by how monomers, dimers, trimers etc., attach to and detach from each other. It is for this reasons that researchers have proposed a plethora of pathways to explain the kinetics of various self-assembling supramolecules,