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Roozbeh Hajiraissi, Ignacio Giner, Guido Grundmeier, Adrian Keller
Misfolding and subsequent assembly of proteins and peptides into insoluble amyloid structures play important roles in the development of numerous diseases. The dynamics of self-assembly and the morphology of the resulting aggregates critically depend on various environmental factors and especially the presence of interfaces. Here, we show in detail how the presence of surfaces with different physicochemical properties impacts assembly dynamics and especially aggregate morphology of hIAPP(20-29), an amyloidogenic fragment of the peptide hormone human islet amyloid polypeptide (hIAPP) which is involved in the development of type 2 diabetes...
December 9, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Jianyuan Zhang, Peter J Santos, Paul A Gabrys, Sangho Lee, Caroline Liu, Robert J Macfarlane
The physical characteristics of composite materials are dictated by both the chemical composition and spatial configuration of each constituent phase. A major challenge in nanoparticle-based composites is developing methods to precisely dictate particle positions at the nanometer length scale, as this would allow complete control over nanocomposite structure-property relationships. In this work, we present a new class of building blocks called nanocomposite tectons (NCTs), which consist of inorganic nanoparticles grafted with a dense layer of polymer chains that terminate in molecular recognition units capable of programmed supramolecular bonding...
December 9, 2016: Journal of the American Chemical Society
Ruochen Fang, Huacheng Zhang, Liulin Yang, Huanting Wang, Ye Tian, Xi Zhang, Lei Jiang
Artificial nanochannels, inheriting smart gating functions of biological ion channels, promote the development of artificial functional nanofluidic devices for high-performance biosensing and electricity generation. However, gating states of the artificial nanochannels have been mainly realized through chemical modification of the channels with responsive molecules, and their gating states cannot be further regulated once the nanochannel is modified. In this work, we employed a new supramolecular layer-by-layer (LbL) self-assembly method to achieve reversible and adjustable multiple gating features in nanofluidic diodes...
December 9, 2016: Journal of the American Chemical Society
Sung Ho Jung, Ka Young Kim, Ji Ha Lee, Cheol Joo Moon, Noh Soo Han, Su-Jin Park, Dongmin Kang, Jae Kyu Song, Shim Sung Lee, Myong Yong Choi, Justyn Jaworski, Jong Hwa Jung
To more accurately assess the pathways of biological systems, a probe is needed that may respond selectively to adenosine triphosphate (ATP) for both in vitro and in vivo detection modes. We have developed a luminescence probe that can provide real-time information on the extent of ATP, ADP, and AMP by virtue of the luminescence and luminescence lifetime observed from a supramolecular polymer based on a C3 symmetrical terpyridine complex with Tb3+ (S1-Tb). The probe shows remarkable selective luminescence enhancement in the presence of ATP compared to other phosphate displaying nucleotides including adenosine diphosphate (ADP), adenosine monophosphate (AMP), guanosine triphosphate (GTP), thymidine triphosphate (TTP), H2PO4- (Pi), and pyrophosphate (PPi)...
December 9, 2016: ACS Applied Materials & Interfaces
Jianhao Wang, Jie Fan, Jinchen Li, Li Liu, Jianpeng Wang, Pengju Jiang, Xiaoqian Liu, Lin Qiu
Herein, a Förster resonance energy transfer system was designed, which consisted of CdSe/ZnS quantum dots donor and mCherry fluorescent protein acceptor. The quantum dots and the mCherry proteins were conjugated to permit Förster resonance energy transfer. Capillary electrophoresis with fluorescence detection was used for the analyses for the described system. The quantum dots and mCherry were sequentially injected into the capillary, while the real-time fluorescence signal of donor and acceptor was simultaneously monitored by two channels with fixed wavelength detectors...
December 9, 2016: Journal of Separation Science
Honglei Zhan, Jun F Liang
Non-covalent polymers have remarkable advantages over synthetic polymers for wide biomedical applications. In this study, non-covalent polymers from self-assembled boric acid were used as the capping reagent to replace synthetic polymers in drug crystallization. Under acidic pH, boric acid self-assembled on the surface of drug nanocrystals to form polymers with network-like structures held together by hydrogen bonds. Coating driven by boric acid self-assembly had negligible effects on drug crystallinity and structure but resulted in drug nanocrystals with excellent dispersion properties that aided in the formation of a more stable suspension...
December 9, 2016: Scientific Reports
Yuqiao Sun, Yongnu Zhang, Lingling Tian, Yuyuan Zhao, Dongni Wu, Wei Xue, Seeram Ramakrishna, Wutian Wu, Liumin He
In the current study, we present three designer self-assembling peptides (SAPs) by appending RADA 16-I with epitopes IKVAV, RGD, and YIGSR, which have different net charges and amphiphilic properties at neutral pH. The self-assembly of the designer SAPs is intensively investigated as a function of pH, canion type, and assembly time. The morphologies of the designer SAPs were studied by atomic force microscope. The secondary structure was investigated by circular dichroism. The dynamic viscoelasticity of designer SAP solutions was examined during titration with different alkaline reagents...
December 9, 2016: Biomedical Materials
Junying Weng, Xiaoyun Li, Ying Guan, X X Zhu, Yongjun Zhang
2D colloidal crystals (CCs) have important applications; however, the fabrication of large-area, high-quality 2D CCs is still far from being trivial, and the fabrication of 2D microgel CCs is even harder. Here, we have demonstrated that they can be facilely fabricated using charge-reversible substrates. The charge-reversible substrates were prepared by modification with amino groups. The amino groups were then protected by amidation with 2,2-dimethylsuccinic anhydride. At acidic pH, the surface charge of the modified substrate will change from negative to positive as a result of the hydrolysis of the amide bonds and the regeneration of the amino groups...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Baofang Zhang, Jie Song, Dong Li, Lang Hu, Craig L Hill, Tianbo Liu
Two novel polyoxovanadate (POV)-containing fluorosurfactants, each with two hydrophobic fluorinated "tails" and one nanosized, hydrophilic, rigid POV "head group", are synthesized for the first time. They self-assemble into spherical, bilayer vesicles in acetonitrile/water mixed solvents, as evidenced by systemic studies using laser light scattering (LLS) and electron microscopy techniques. The vesicle sizes demonstrate dynamic change over different solvent compositions mainly as a result of the solvent swelling of the fluorocarbon chains, although the charge number on the POVs changes over the solvent polarity as well...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Kuan-Yi Tsao, Hui-Ping Tsai, Kun-Yi Andrew Lin, Yi-Xuan He, Hongta Yang
This study reports a self-assembly technology for fabricating retroreflection coatings with hierarchical nano-/microstructures, which are inspired by the binary periodic structures found in the compound eyes of insects. Silica colloidal crystals of adjustable thicknesses are assembled on encountering glass microbeads using a Langmuir-Blodgett-like approach in a layer-by-layer manner. The as-assembled hierarchical structures exhibit a brilliant color caused by Bragg diffraction from the crystalline lattice of silica colloidal crystals on glass microbeads...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Birte Martin-Bertelsen, Anan Yaghmur, Henrik Franzyk, Sarah Justesen, Jacob J K Kirkensgaard, Camilla Foged
Synthetic analogues of the cell-wall lipid monomycoloyl glycerol (MMG) are promising as next-generation vaccine adjuvants. In the present study, the thermotropic phase behavior of an array of synthetic MMG analogues was examined by using simultaneous small- and wide-angle X-ray scattering under excess water conditions. The MMG analogues differed in the alkyl chain lengths and in the stereochemistry of the polar glycerol headgroup or of the lipid tails (native-like versus alternative compounds). All MMG analogues formed poorly hydrated lamellar phases at low temperatures and inverse hexagonal (H2) phases at higher temperatures prior to melting...
December 6, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Li Zhang, Dezhi He, Yudong Liu, Kun Wang, Zongxia Guo, Jianbin Lin, Hui-Jun Zhang
A series of 2,5,8,11-tetraalkenyl perylene bisimide (PBI) derivatives were synthesized through Ru(II)- or Rh(III)-catalyzed regio- and steroselective oxidative C-H olefination in one step. The optical electronic and self-assembly of the 2,5,8,11-substituted PBIs were investigated, which showed great potential in optoelectronic applications.
November 18, 2016: Organic Letters
Ghénadie Novitchi, Sergiu Shova, Yanhua Lan, Wolfgang Wernsdorfer, Cyrille Train
The versatile verdazyl family provides a new member as its reduced form 1,5-dimethyl-3-[3'-(hydroxymethyl)-2'-pyridine]-6-oxotetrazane (H3vdpyCH2OH). Upon oxidation and deprotonation in the presence of the acetate salts of Co(II) and Dy(III), the vdpyCH2OH radical is able to self-assemble [(vdpyCH2O)2Co2Dy2ac8] (Hac = HO2CCH3), a 2p-3d-4f cluster displaying single-molecule-magnet properties.
December 5, 2016: Inorganic Chemistry
Manik Lal Saha, Michael Schmittel
Herein, we demonstrate how the supramolecular complexity (evaluated by the degree of self-sorting M) evolves in a chemical cycle of cascaded metallosupramolecular transformations, using abiological self-assembled entities as input signals. Specifically, the successive addition of the supramolecular self-assembled structures S1 and (T2 + S2) to the starting supramolecular two-component equilateral triangle T1 (M = 1) first induced a fusion into the three-component quadrilateral R1 (M = 6) and then to the five-component scalene triangle T3 (M = 16)...
December 5, 2016: Inorganic Chemistry
Rong-Jia Wei, Takuya Shiga, Graham N Newton, David Robinson, Sadamu Takeda, Hiroki Oshio
A cage complex, H2O@[Co5Fe4], was found to encapsulate two water molecules during its self-assembly. The complex exhibited remarkable multifunctionality, combining magnetic switching from the thermal electron-transfer-coupled spin transition of the cage host and dipolar reorientational motion of the confined water, as evidenced by permittivity measurements, density functional theory calculations, and solid-state (2)H NMR spectra.
December 5, 2016: Inorganic Chemistry
Wenjun Peng, Sen Xu, Lei Li, Chongyin Zhang, Sixun Zheng
Organic-inorganic nanocomposites composed of polyhedral oligomeric silsesquioxane (POSS) and epoxy resin were prepared via self-assembly of an amphiphilic triblock copolymer bearing a poly(POSS) midblock in epoxy thermosets. First, this organic-inorganic amphiphilic triblock copolymer was synthesized via hydrosilylation of heptaphenylhydro POSS with an existing triblock copolymer containing a short polybutadiene midblock. It was found that this novel amphiphilic block copolymer can self-assemble into nanophases in epoxy thermosets...
November 23, 2016: Journal of Physical Chemistry. B
Joseph S Melinger, Ruojie Sha, Chengde Mao, Nadrian C Seeman, Mario G Ancona
DNA crystals make it possible to organize guest molecules into specific periodic 3D patterns at the nanoscale, and thereby to create novel macroscopic objects with potentially useful functionality. Here, we describe the fluorescence and energy transfer properties of DNA crystals that are self-assembled from DNA tensegrity triangles with covalently attached Cy3 and Cy5 dyes. When compared to reference DNA strands in solution, the fluorescence measurements indicate that the dyes in the crystal experience a more homogeneous environment, resulting in a 2-fold increase in Cy3 quantum yield and single-exponential Cy3 fluorescence decays...
December 8, 2016: Journal of Physical Chemistry. B
Wei-Tsung Chuang, Yan-Ming Hsu, En-Li Lin, I-Ming Lin, Ya-Sen Sun, Yeo-Wan Chiang, Chun-Jen Su, Yao-Chang Lee, U-Ser Jeng
In this work, we introduce a facile method based on host-guest chemistry to synthesize a range of nanostructured TiO2 materials using supramolecular templates of a dendron-jacketed block copolymer (DJBCP). The DJBCP is composed of amphiphilic dendrons (4'-(3,4,5-tridodecyloxybenzoyloxy)benzoic acid, TDB) selectively incorporated into a P4VP block of polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) via hydrogen bonding. The PS-b-P4VP host acts as a structure-directing template, while the guest molecules (TDB) assist the self-assembly nanostructures and zone-axis alignment, resulting in the nanostructured template of vertically oriented cylinders formed via successive phase transformations from Im3̅m to R3̅m to P6mm upon thermal annealing in the doctor-blade-cast film...
December 7, 2016: ACS Applied Materials & Interfaces
Teng Zhang, Ashley R Gans-Forrest, Eungkyu Lee, Xueqiang Zhang, Chen Qu, Yunsong Pang, Fangyuan Sun, Tengfei Luo
The nature of the bond is a dominant factor in determining the thermal transport across interfaces. In this paper, we study the role of the hydrogen bond in thermal transport across interfaces between hard and soft materials with different surface functionalizations around room temperature using molecular dynamics simulations. Gold (Au) is studied as the hard material, and four different types of organic liquids with different polarizations, including hexane (C5H11CH3), hexanamine (C6H13NH2), hexanol (C6H13OH), and hexanoic acid (C5H11COOH), are used to represent the soft materials...
December 7, 2016: ACS Applied Materials & Interfaces
Fatemeh Sadat Minaye Hashemi, Bradlee R Birchansky, Stacey F Bent
Area selective atomic layer deposition has the potential to significantly improve current fabrication approaches by introducing a bottom-up process in which robust and conformal thin films are selectively deposited onto patterned substrates. In this paper, we demonstrate selective deposition of dielectrics on metal/dielectric patterns by protecting metal surfaces using alkanethiol blocking layers. We examine alkanethiol self-assembled monolayers (SAMs) with two different chain lengths deposited both in vapor and in solution and show that in both systems, thiols have the ability to block surfaces against dielectric deposition...
December 7, 2016: ACS Applied Materials & Interfaces
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