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https://www.readbyqxmd.com/read/28922602/cucurbit-7-uril-induced-formation-of-fret-enabled-uni-lamellar-lipid-vesicles
#1
Shilpi Kushwaha, Arunava Maity, Monalisa Gangopadhyay, Sapna Ravindranathan, Pattuparambil R Rajamohanan, Amitava Das
A unique fluorescence resonance energy transfer (FRET) process is found to be operational in a unilamellar lipid self-assembly in the aqueous phase. A newly synthesized naphthyl based long chain lipid derivative [N-(naphthalene-1-ylmethyl)tetradecane-1-ammonium chloride, 14NA+] forms various self-assembled architectures in the aqueous phase. Controlled changes in lipid concentration lead to a transition of the self-assemblies from micelles to vesicles to rods. In the presence of cucurbit[7]uril (CB7), 14NA+ forms a host-guest [2]pseudorotaxane complex (CB7∋14NA+) and secondary interactions lead to the formation of a lipid bilayer with hydrophobic pockets situated in between the layers...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28922537/encapsulation-of-isolated-luminophores-within-supramolecular-cages
#2
Marcel Handke, Takuji Adachi, Chunhua Hu, Michael D Ward
The sequestration of luminophores within supramolecular polyhedral compartments of a crystalline zeolite-like hydrogen-bonded framework illustrates a unique approach to limiting the self-quenching ordinarily exhibited at the high concentrations achievable in this framework. A range of differently sized luminescent guests, namely coumarin 1, coumarin 4, fluorescein, [Ru(bpy)3 ]Cl2 , and rhodamine B, can be encapsulated in amounts of up to one molecule per cage, equivalent to a concentration of 0.175 m, which is significantly higher than the concentration at which aggregation-induced quenching occurs in other media...
September 18, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28922509/molecular-switching-in-confined-spaces-effects-of-encapsulating-the-dha-vhf-photo-switch-in-cucurbiturils
#3
Michael Å Petersen, Brian Rasmussen, Nicolaj N Andersen, Stephan P A Sauer, Mogens Brøndsted Nielsen, Sophie R Beeren, Michael Pittelkow
Confinement of reactive chemical species uniquely affects chemical reactivity by restricting the physical space available and by restricting access to interactions with the solvent. In Nature, for example, confined protein binding pockets govern processes following photoisomerization reactions and the isomerizations themselves. Here we describe the first example of a dihydroazulene/vinylheptafulvene (DHA/VHF) photo-switch functioning in water, and we show how its switching behavior is strongly influenced by supramolecular interactions with a series of cucurbit[n]uril (CB) host molecules...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28922481/photo-induced-assembly-of-a-luminescent-tetraruthenium-square
#4
Baptiste Laramée-Milette, Francesco Nastasi, Fausto Puntoriero, Sebastiano Campagna, Garry S Hanan
Self-assembly is a powerful synthetic tool that has led to the development of one-, two- and three-dimensional architectures. From MOFs to molecular flasks, self-assembled materials have proven to be of great interest to the scientific community. Here we describe a strategy for the construction and de-construction of a supramolecular structure through unprecedented photo-induced assembly and dis-assembly. The combination of two approaches, a [n×1]-directional bonding strategy and a ligand photo-dissociation strategy, allows the photo-induced assembly of a polypyridyl Ru(II) precursor into a discrete molecular square...
September 18, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28920601/dynamics-of-coherence-localization-and-excitation-transfer-in-disordered-nanorings
#5
Alejandro D Somoza, Ke-Wei Sun, Rafael A Molina, Yang Zhao
Self-assembled supramolecular aggregates are excellent candidates for the design of efficient excitation transport devices. Both artificially prepared and natural photosynthetic aggregates in plants and bacteria present an important degree of disorder that is supposed to hinder excitation transport. Besides, molecular excitations couple to nuclear motion affecting excitation transport in a variety of ways. We present an exhaustive study of exciton dynamics in disordered nanorings with long-range interactions under the influence of a phonon bath taking the LH2 system of purple bacteria as a model...
September 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28920442/novelty-of-dynamic-process-in-the-synthesis-of-biocompatible-silica-nanotubes-by-biomimetic-glycyldodecylamide-as-a-soft-template
#6
Hyejung Choi, Joong-Jo Kim, Yong-Hwan Mo, Benjaram Mahipal Reddy
Dynamic process in the synthesis of silica nanotubes (SNTs) by utilizing glycyldodecylamide (GDA) as a soft template was thoroughly investigated. The morphological evolution from GDA to SNTs was deeply explored to elucidate the formation mechanism for optimizing the synthesis procedure. Various analytical tools, namely, XRD, FTIR, SEM, TEM, Z-potential, and N2 adsorption/desorption isotherms were employed during the synthesis procedure. The interactive structure of GDA was also investigated using TEM-EDX as a function of aging time...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28920077/mimicking-the-bioactivity-of-fibroblast-growth-factor-2-using-supramolecular-nanoribbons
#7
Charles M Rubert Pérez, Zaida Álvarez, Feng Chen, Taner Aytun, Samuel I Stupp
Fibroblast growth factor (FGF-2) is a multifunctional growth factor that has pleiotropic effects in different tissues and organs. In particular, FGF-2 has a special role in angiogenesis, an important process in development, wound healing, cell survival, and differentiation. Therefore, incorporating biological agents like FGF-2 within therapeutic biomaterials is a potential strategy to create angiogenic bioactivity for the repair of damaged tissue caused by trauma or complications that arise from age and/or disease...
September 11, 2017: ACS Biomaterials Science & Engineering
https://www.readbyqxmd.com/read/28919501/structural-and-kinetics-characterization-of-the-f1f0-atp-synthase-dimer-new-repercussion-of-monomer-monomer-contact
#8
Mercedes Esparza-Perusquía, Sofía Olvera-Sánchez, Juan Pablo Pardo, Guillermo Mendoza-Hernández, Federico Martínez, Oscar Flores-Herrera
Ustilago maydis is an aerobic basidiomycete that fully depends on oxidative phosphorylation for its supply of ATP, pointing to mitochondria as a key player in the energy metabolism of this organism. Mitochondrial F1F0-ATP synthase occurs in supramolecular structures. In this work, we isolated the monomer (640kDa) and the dimer (1280kDa) and characterized their subunit composition and kinetics of ATP hydrolysis. Mass spectrometry revealed that dimerizing subunits e and g were present in the dimer but not in the monomer...
September 14, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28918640/supramolecular-interaction-assisted-fluorescence-and-tunable-stimuli-responsiveness-of-l-phenylalanine-based-polymers
#9
Mridula Nandi, Binoy Maiti, Kambalapalli Srikanth, Priyadarsi De
Supramolecular host-guest interaction between randomly methylated β-cyclodextrin (RM β-CD) and side-chain phenylalanine (Phe) and Phe-Phe dipeptide based homopolymers has been employed for amplification of fluorescence emission of otherwise weakly fluorescent amino acid Phe. The host-guest complex has been characterized by 1H and 13C NMR spectroscopy, two-dimensional (2D) rotating-frame overhauser spectroscopy (ROESY), FT-IR, UV-visible and fluorescence spectroscopy. To gain insights into the origin of fluorescence in homopolymers, density functional theory (DFT) calculations were performed where phenyl moieties inside the less polar core of β-CD were observed to form π-π coupled complex resulting in enhanced emission...
September 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28917848/development-and-characterization-of-ricinoleic-acid-based-sulfhydryl-thiol-and-ethyl-cellulose-blended-membranes
#10
Mei Li, Jianling Xia, Chengxiang Ding, Wei Mao, Haiyang Ding, Lina Xu, Shouhai Li
Ethyl cellulose (EC) membranes can be combined with efficient plasticizers derived from renewable resources to form supramolecular systems. In this paper, a novel ricinoleic acid-based sulfhydryl triol (STRA) was first synthesized and used as a plasticizer for EC membranes. A supramolecular membrane of EC and STRA using van der Waals forces was designed. The morphology, hydrophilic performance, thermal stability, and mechanical properties of the composites were investigated. While pure EC is brittle, its membrane ductility and hydrophilic performance can be improved by integration with STRA...
November 1, 2017: Carbohydrate Polymers
https://www.readbyqxmd.com/read/28915384/supramolecular-nano-sniffers-for-ultrasensitive-detection-of-formaldehyde
#11
Uchangi Satyaprasad Akshath, Praveena Bhatt
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...
September 9, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28914942/a-room-temperature-reversible-phase-transition-containing-dielectric-switching-of-a-host-guest-supramolecular-metal-halide-compound
#12
Yang Lu, Xiu-Ni Hua, Wei-Qiang Liao, Ji-Xing Gao, Zi Yin
Following our recent findings on dielectric materials, we synthesized a new host-guest supramolecular metal-halide compound, [(2-AMPD)(18-crown-6)]CuCl4 (1, 2-AMPD = 2-aminomethylpiperidinium). Systematic characterization techniques such as variable-temperature crystal structure analyses, differential scanning calorimetry (DSC) measurements, temperature-dependent dielectric measurements and powder X-ray diffraction (PXRD) measurements demonstrate that 1 undergoes a reversible phase transition at room temperature, accompanied by switchable dielectric responses and remarkable anisotropy along three different crystallographic axes...
September 15, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28914532/aggregation-induced-electrochemiluminescence-of-platinum-ii-complexes
#13
Serena Carrara, Alessandro Aliprandi, Conor F Hogan, Luisa De Cola
We report the electrochemiluminescence properties of square-planar Pt(II) complexes which result from the formation of supramolecular nanostructures. We define this new phenomenon as Aggregation-Induced Electrochemiluminescence (AIECL). In this system, self-assembly changes the HOMO and LUMO energies, making their population accessible via ECL pathways and leading to the generation of the luminescent excited state. Significantly, the emission from the self-assembled system is the first example of Electro-chemiluminescence (ECL) of Pt(II) complexes in aque-ous solution having higher efficiency than the standard, Ru(bpy)32+...
September 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28914496/silver-thiolate-nano-sized-molecular-clusters-and-their-supramolecular-covalent-frameworks-an-approach-toward-pre-templated-synthesis
#14
Zi-Yi Chen, Dennis Y S Tam, Leon Li-Min Zhang, Thomas Chung Wai Mak
A series of seven new complexes including silver-thiolate molecular clusters and their covalent supramolecular frameworks have been assembled from the silver carbide precursor Ag2C2 using a C22- pre-templated approach. Herein, two prototype clusters Ag14(SR)6 and CO3@Agm(SR)10 (R = isopropyl, cyclohexyl or tert-butyl; m = 18 or 20) are employed to construct cluster-based metal-organic frameworks of different dimensions. In particular, both new ellipsoidal tetradecanuclear molecular cluster compounds, namely Ag14(S-iPr)6(CF3CO2)8·DMSO6 (two polymorphic forms 1, 2) and [Ag14(S-Cy)6(CO2CF3)8(DMSO)4] · DMSO3 (3), and a cluster-based metal-organic framework {Ag3[Ag14(S-iPr)6(CF3CO2)11(H2O)3CH3OH] · (H2O)2...
September 15, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28914466/supramolecular-hydro-and-ionogels-a-study-of-their-properties-and-antibacterial-activity
#15
Carla Rizzo, Rossella Arrigo, Nadka Tz Dintcheva, Giuseppe Gallo, Francesco Giannici, Renato Noto, Alberto Sutera, Paola Vitale, Francesca D'Anna
Diimidazolium-based organic salts, bearing peptides or aminoacids as anions, have been synthesized and tested for their gelling ability in biocompatible solvents. These low molecular weight salts were successfully used as gelators in phosphate saline buffer and ionic liquids. Then, properties of obtained soft materials were analyzed in terms of melting temperature and gel strength as accounted for by rheological investigation. Gel phase formation was studied using UV-vis and resonance light scattering measurements, whereas morphology of soft materials was analysed using polarized optical microscopy and scanning electron microscopy...
September 15, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28914395/repetitive-on-demand-drug-release-from-polymeric-matrices-containing-a-macroscopic-spherical-iron-core
#16
Stefan A Rovers, Maartje F Kemmere, Jos T F Keurentjes, Richard Hoogenboom
A system for multiple on-demand drug release has been prepared that can be activated with an alternating magnetic field as external trigger. The core/shell samples have been developed based on a macroscopic spherical iron core coated with a thermoresponsive polymer, poly(styrene-stat-butyl methacrylate), containing ibuprofen as a model drug. During exposure of the samples to the magnetic field (ON state), the release rate of ibuprofen is significantly increased, up to 35 times the release rate without the magnetic field (OFF state)...
September 15, 2017: Journal of Materials Science. Materials in Medicine
https://www.readbyqxmd.com/read/28913864/strand-displacement-in-coiled-coil-structures-controlled-induction-and-reversal-of-proximity
#17
Katharina Gröger, Georgina Gavins, Oliver Seitz
Coiled-coil peptides are frequently used to create new function upon self-assembly of supramolecular complexes. A multitude of coil peptide sequences provides control over specificity and stability of coiled-coil complexes. However, comparably little attention has been paid to the development of methods that allow for the reversal of complex formation under non-denaturing conditions. Herein, we present a reversible 2-state switching system. The process involves two peptide molecules for formation of a size-mismatched coiled-coil duplex and a third, disruptor peptide which targets an overhanging end...
September 15, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28913857/dynamic-molecular-invasion-into-multiply-interlocked-catenane
#18
Yasuyuki Yamada, Ryohei Ito, Sayaka Ogino, Tatsuhisa Kato, Kentaro Tanaka
A multiply interlocked catenane with a novel molecular topology was synthesized; a phthalocyanine bearing four peripheral crown ethers was quadruply interlocked with a cofacial porphyrin dimer bridged with four alkylammonium chains. The supramolecular conjugate has two nanospaces surrounded by a porphyrin, a phthalocyanine, and four alkyl chains to accommodate guest molecules. Because the phthalocyanine is movable along the alkyl chains, it acts as an adjustable wall, permitting the invasion of large molecules to the nanospaces without spoiling the affinity of the association...
September 14, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28910515/chiral-kagome-lattices-from-on-surface-synthesized-molecules
#19
Tao Wang, Qitang Fan, Lin Feng, Zhijie Tao, Jianmin Huang, Huanxin Ju, Qian Xu, Shanwei Hu, Junfa Zhu
Kagome lattices have attracted much attention due to their potential applications in spin-frustrated magnetism and host-guest chemistry. Examples toward the fabrication of 2D Kagome lattices reported previously have a common feature that the precursor molecules were typically structurally intact on surface with no chemical reactions accompanied. Herein, with the combined synchrotron radiation photoelectron spectroscopy (SRPES) and scanning tunneling microscopy (STM), we demonstrated that two types of chiral Kagome lattices from on-surface synthesized organometallic compounds were fabricated, which are known as intermediates of Glaser coupling on silver single crystal surfaces...
September 14, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/28905963/coarse-grained-molecular-dynamics-studies-of-the-structure-and-stability-of-peptide-based-drug-amphiphile-filaments
#20
Myungshim Kang, Honggang Cui, Sharon M Loverde
Peptide-based supramolecular filaments, in particular filaments self-assembled by drug amphiphiles (DAs), possess great potential in the field of drug delivery. These filaments possess one hundred percent drug loading, with a release mechanism that can be tuned based on the dissociation of the supramolecular filaments and the degradation of the DAs [Cheetham et al., J. Am. Chem. Soc., 2013, 135(8), 2907]. Recently, much attention has been drawn to the competing intermolecular interactions that drive the self-assembly of peptide-based amphiphiles into supramolecular filaments...
September 14, 2017: Soft Matter
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