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Cationic polymers

Gil Henkin, Daniel Berard, Francis Stabile, Marjan Shayegan, Jason S Leith, Sabrina R Leslie
We present a dynamically adjustable nanofluidic platform for formatting the conformations of and visualizing the interaction kinetics between biomolecules in solution, offering new time resolution and control of the reaction processes. This platform extends Convex Lens-induced Confinement (CLiC), a technique for imaging molecules under confinement, by introducing a system for in-situ modification of the chemical environment; this system uses a deep microchannel to diffusively exchange reagents within the nanoscale imaging region, whose height is fixed by a nanopost array...
October 21, 2016: Analytical Chemistry
Christophe Kahlfuss, Sandrine Denis-Quanquin, Nathalie Calin, Elise Dumont, Marco Garavelli, Guy Royal, Saioa Cobo, Eric Saint-Aman, Christophe Bucher
Viologen-centered electron transfer is used to trigger a complete dissociation of a porphyrin-based coordination polymer. In the oxidized state, self-assembly is induced by iterative association of individual porphyrin-based tectons. Dissociation of the self-assembled species is actuated upon changing the redox state of the bipyridium units involved in the tectons from their dicationic state to their radical cation state, the driving force of the disassembling process being the formation of an intramolecularly locked conformation partly stabilized by π-dimerization of both viologen cation radicals...
October 21, 2016: Journal of the American Chemical Society
Chao Jiang, Yuan Yuan, Guang Yang, Yan Jin, Libing Liu, Yuyang Zhao, Luqi Huang
Inaccurate labeling of materials used in herbal products may compromise the therapeutic efficacy and may pose a threat to medicinal safety. In this paper, a rapid (within 3 h), sensitive and visual colorimetric method for identifying substitutions in terminal market products was developed using cationic conjugated polymer-based fluorescence resonance energy transfer (CCP-based FRET). Chinese medicinal materials with similar morphology and chemical composition were clearly distinguished by the single-nucleotide polymorphism (SNP) genotyping method...
October 21, 2016: Scientific Reports
Yujing Li, Xueqin Huang, Robert J Lee, Yuhang Qi, Kaikai Wang, Fei Hao, Yu Zhang, Jiahui Lu, Qingfan Meng, Shuai Li, Jing Xie, Lesheng Teng
Polyethylenimine (PEI) as a cationic polymer is commonly used as a carrier for gene delivery. PEI-800 is less toxic than PEI-25K but it is also less efficient. A novel nanocarrier was developed by combining PEI-800 with a pH-sensitive lipid to form polymer-lipid hybrid nanoparticles (P/LNPs). They were synthesized by microfluidic focusing (MF). Two microfluidic devices were used to synthesize P/LNPs loaded with VEGF siRNA. A series of P/LNPs with different particle sizes and distributions were obtained by altering the flow rate and geometry of microfluidic chips, and introducing sonication...
October 17, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Mordjane Boukhet, Fabien Piguet, Hadjer Ouldali, Manuela Pastoriza-Gallego, Juan Pelta, Abdelghani Oukhaled
The transport of macromolecules through nanopores is involved in many biological functions and is today at the basis of promising technological applications. Nevertheless the interpretation of the dynamics of the macromolecule/nanopore interaction is still misunderstood and under debate. At the nanoscale, inside biomimetic channels under an external applied voltage, electrophoresis, which is the electric force acting on electrically charged molecules, and electroosmotic flow (EOF), which is the fluid transport associated with ions, contribute to the direction and magnitude of the molecular transport...
October 20, 2016: Nanoscale
Junyi Che, Anqi Tao, Shun Chen, Xiaoming Li, Yi Zhao, Weien Yuan
Small interfering RNA (siRNA) has increased the hope for highly-efficient treatment of gene-related diseases. However, the stable and efficient delivery of therapeutic nucleic acids is a prerequisite for the successful clinical translation of RNA interfering therapy. To achieve this, we condensed the low molecular weight polyethyleneimine (PEI, Mw < 2000) with 2,6-pyridinedicarboxaldehyde (PDA) to synthesize a biologically responsive and degradable cationic polymer (abbreviated to PDAPEI) which was utilized as a gene vector for the delivery of a VEGF-A shRNA expression plasmid DNA (pDNA)...
October 19, 2016: Scientific Reports
Junxue An, Xiaoyan Liu, Andra Dedinaite, Evgeniya Korchagina, Francoise M Winnik, Per M Claesson
Equilibration in adsorbing polymer systems can be very slow, leading to different physical properties at a given condition depending on the pathway that was used to reach this state. Here we explore this phenomenon using a diblock copolymer consisting of a cationic anchor block and a thermoresponsive block of poly(2-isopropyl-2-oxazoline), PIPOZ. We find that at a given temperature different polymer chain densities at the silica surface are achieved depending on the previous temperature history. We explore how this affects surface and friction forces between such layers using the atomic force microscope colloidal probe technique...
October 12, 2016: Journal of Colloid and Interface Science
Andrea Träger, Samuel A Pendergraph, Torbjörn Pettersson, Tobias Halthur, Tommy Nylander, Anna Carlmark, Lars Wågberg
In this study the wet adhesion between Layer-by-Layer (LbL) assembled films of triblock copolymer micelles was investigated. Through the LbL assembly of triblock copolymer micelles with hydrophobic, low glass transition temperature (Tg) middle blocks and ionic outer blocks, a network of energy dissipating polymer chains with electrostatic interactions serving as crosslinks can be built. Four triblock copolymers were synthesized through Atom Transfer Radical Polymerisation (ATRP). One pair had a poly(2-ethyl-hexyl methacrylate) middle block with cationic or anionic outer blocks...
October 18, 2016: Nanoscale
Teresa F Mastropietro, Nadia Marino, Giovanni De Munno, Francesc Lloret, Miguel Julve, Emilio Pardo, Donatella Armentano
The preparation and structural characterization of four novel oxalate-based iron(III) compounds of formulas {(MeNH3)2[Fe2(ox)2Cl4]·2.5H2O}n (1), K(MeNH3)[Fe(ox)Cl3(H2O)] (2), {MeNH3[Fe2(OH)(ox)2Cl2]·2H2O}n (3), and {(H3O)(MeNH3)[Fe2O(ox)2Cl2]·3H2O}n (4) (MeNH3(+) = methylammonium cation and H2ox = oxalic acid) are reported here. 1 is an anionic waving chain of oxalato-bridged iron(III) ions with peripheral chloro ligands, the charge balance being ensured by methylammonium cations. 2 is a mononuclear complex with a bidentate oxalate, three terminal chloro ligands, and a coordinated water molecule achieving the six-coordination around each iron(III) ion...
October 17, 2016: Inorganic Chemistry
Cédric Gaillard, Yunhui Wang, Rudy Covis, Thomas Vives, Maud Benoit, Thierry Benvegnu
This article contains data on the Laser Scanning Confocal Microscopy (LSCM) and Transmission Electron Microscopy (TEM) images related to multi-scaled self-assemblies resulting from 'green' cationic glycine betaine surfactant/anionic kappa-carrageenan interactions. These data gave clear evidence of the evolution of the micron-, nano-sized structures obtained at two surfactant/polymer molar ratios (3.5 and 0.8) and after the dilution of the aqueous dispersions with factors of 5 and 10 times. This data article is related to the research article entitled, "Monitoring the architecture of anionic ĸ-carrageenan/cationic glycine betaine amide surfactant assemblies by dilution: A multiscale approach" (Gaillard et al...
December 2016: Data in Brief
Rosemeyre A Cordeiro, Daniela Santo, Dina Farinha, Arménio Serra, Henrique Faneca, Jorge F J Coelho
: Cationic polymer-based vectors have been considered a promising strategy in gene therapy area due to their inherent ability to condense genetic material and successfully transfect cells. However, they usually exhibit high cytotoxicity. In this work, it is proposed the use of a tailor-made gene carrier based on a tri-block copolymer of poly[2-(dimethylamino)ethyl methacrylate] and poly(β-amino ester) (PDMAEMA-b-PβAE-b-PDMAEMA), the influence of the PβAE length being assessed. For this purpose, three different block copolymers were prepared varying the molecular weight of this segment...
October 12, 2016: Acta Biomaterialia
Jennifer Gamboa Jackman, Hemraj Juwarker, Luke P Poveromo, Howard Levinson, Kam W Leong, Bruce A Sullenger
Dying cells release nucleic acids (NA) and NA-containing complexes that activate inflammatory pathways of immune cells. Sustained activation of these pathways contributes to chronic inflammation frequently encountered in autoimmune and inflammatory diseases. In this study, grafting of cationic polymers onto a nanofibrous mesh enabled local scavenging of negatively charged pro-inflammatory molecules in the extracellular space. Nucleic acid scavenging nanofibers (NASFs) formed from poly(styrene-alt-maleic anhydride) conjugated with 1...
October 14, 2016: Biomacromolecules
Sireenart Surinwong, Nobuto Yoshinari, Tatsuhiro Kojima, Takumi Konno
A unique pH-controlled synthesis of two metallosupramolecular structures from CoAu complex anions and Zn(II) cations is reported. A dense coordination polymer (porosity ∼13%) was formed at a pH of 5.0, whereas a porous ionic framework (porosity ∼61%) that selectively adsorbs CO2 and H2O was created when the pH was adjusted to 5.5.
October 14, 2016: Chemical Communications: Chem Comm
Yuran Xie, Bryan Killinger, Anna Moszczynska, Olivia M Merkel
The use of small interference RNA (siRNA) to target oncogenes is a promising treatment approach for cancer. However, siRNA cancer therapies are hindered by poor delivery of siRNA to cancer cells. Transferrin receptor (TfR) is overexpressed in many types of tumor cells and therefore is a potential target for the selective delivery of siRNA to cancer cells. Here, we used the TfR binding peptide HAIYPRH (HAI peptide) conjugated to cationic polymer branched polyethylenimine (bPEI), optimized the coupling strategy, and the TfR selective delivery of siRNA was evaluated in cells with high (H1299) and low TfR expression (A549 and H460)...
October 10, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
John K Riley, Robert D Tilton
This work investigates surface forces that result from adsorbed layers of silica nanoparticles with grafted pH-responsive, cationic poly(2-(dimethylamino)ethyl methacrylate) brushes (SiO2-g-PDMAEMA), and how adhesive bridging forces can be suppressed and friction forces reduced by "backfilling" these heterogeneous adsorbed layers with nonionic poly(ethylene oxide) star copolymers (Star PEO45MA). Adsorption of SiO2-g-PDMAEMA and Star PEO45MA to silica is measured as a function of pH by quartz crystal microbalance with dissipation (QCM-D) in order to evaluate the electrostatically-driven adsorption of SiO2-g-PDMAEMA and hydrogen-bonding driven adsorption of Star PEO45MA...
October 13, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Khaled Belal, François Stoffelbach, Joël Lyskawa, Matthieu Fumagalli, Dominique Hourdet, Alba Marcellan, Lieselot De Smet, Victor R de la Rosa, Graeme Cooke, Richard Hoogenboom, Patrice Woisel
Most polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non-thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT(4+) , swelling occurred as a result of host-guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter-ions embedded in the network...
October 12, 2016: Angewandte Chemie
Jingjing Wu, Cui Tang, Chunhua Yin
In order to reduce toxicity and improve antitumor therapeutic effects of doxorubicin (DOX) and recombinant human interleukin-2 (rhIL-2), we developed a hydrophilic cationic polymer (N,N,N-trimethyl chitosan, TMC) based nanocomplexes (FTCD/rhIL-2) which could efficiently mediate systemic co-delivery of hydrophobic DOX and water-soluble rhIL-2 to achieve the purpose of combination therapy. DOX was covalently conjugated to TMC through cis-aconitic anhydride (CA) which endowed nanocomplexes a pH-sensitive release of DOX, while rhIL-2 was loaded through electrostatic adsorption without compromise of bioactivity...
October 10, 2016: Acta Biomaterialia
Armando Hernandez-Garcia, Aldrik H Velders Velders, Martien Cohen Stuart, Renko de Vries, Jan van Lent, Junyou Wang
We investigate a new case of self-assembly-stimulated self-assembly in which a triblock polypeptide is combined with a anionic coordination polymer of a dipicolinic acid bis-ligand, and d- or f- block metal ions like Zn(II) or Eu(III). The polypeptide not only has a silk-like domain that can fold and stack, but also a C-terminal cationic sequence by which it can interact with the supramolecular (coordination) polyanion. In the presence of all three ingredients (polypeptide, bis-ligand and metal ions), we observe initiation and slow growth of well-defined metal-containing nanorods of up to 150 nm in length, proving that self-assembly of the polypeptide is triggered by the self-assembly of the coordination polyelectrolyte and vice versa...
October 11, 2016: Chemistry: a European Journal
Karina Hoher, Piercarlo F Cardoso, Luiz F Lepre, Rômulo A Ando, Leonardo J A Siqueira
An investigation comprising experimental techniques (absorption capacity of SO2 and vibrational spectroscopy) and molecular simulations (thermodynamics, structure, and dynamics) has been performed for the polymer poly(ethylene oxide) (PEO), the ionic liquid butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N4111][Tf2N]) and their mixtures as sulfur dioxide (SO2) absorbing materials. The polymer PEO has higher capacity to absorb SO2 than the neat ionic liquid, whereas the mixtures presented intermediary absorption capacities...
October 10, 2016: Physical Chemistry Chemical Physics: PCCP
Jen-Yu Liao, Irina Anosova, Saikat Bala, Wade D Van Horn, John C Chaput
G-rich sequences can adopt four-stranded helical structures, called G-quadruplexes, that self-assemble around monovalent cations like sodium (Na(+) ) and potassium (K(+) ). Whether similar structures can be formed from xeno-nucleic acid (XNA) polymers with a shorter backbone repeat unit is an unanswered question with significant implications on the fold space of functional XNA polymers. Here, we examine the potential for TNA (α-L-threofuranosyl nucleic acid) to adopt a four-stranded helical structure based on a planar G-quartet motif...
October 7, 2016: Biopolymers
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