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Cationic polymers

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https://www.readbyqxmd.com/read/28205439/synthesis-of-coordination-polymers-of-tetravalent-actinides-uranium-and-neptunium-with-a-phthalate-or-mellitate-ligand-in-an-aqueous-medium
#1
Nicolas P Martin, Juliane März, Christophe Volkringer, Natacha Henry, Christoph Hennig, Atsushi Ikeda-Ohno, Thierry Loiseau
Four metal-organic coordination polymers bearing uranium or neptunium have been hydrothermally synthesized from a tetravalent actinide chloride (AnCl4) and phthalic (1,2-H2bdc) or mellitic (H6mel) acid in aqueous media at 130 °C. With the phthalate ligand, two analogous assemblies ([AnO(H2O)(1,2-bdc)]2·H2O; An = U(4+) (1) or Np(4+) (2)) have been isolated, in which the square-antiprismatic polyhedra of AnO8 are linked to each other via μ3-oxo groups with an edge-sharing mode to materialize infinite zigzag ribbons...
February 16, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28203100/from-amino-acids-polymers-antimicrobial-peptides-and-histones-to-their-possible-role-in-the-pathogenesis-of-septic-shock-a-historical-perspective
#2
Isaac Ginsburg, Peter Vernon van Heerden, Erez Koren
This paper describes the evolution of our understanding of the biological role played by synthetic and natural antimicrobial cationic peptides and by the highly basic nuclear histones as modulators of infection, postinfectious sequelae, trauma, and coagulation phenomena. The authors discuss the effects of the synthetic polymers of basic poly α amino acids, poly l-lysine, and poly l-arginine on blood coagulation, fibrinolysis, bacterial killing, and blood vessels; the properties of natural and synthetic antimicrobial cationic peptides as potential replacements or adjuncts to antibiotics; polycations as opsonizing agents promoting endocytosis/phagocytosis; polycations and muramidases as activators of autolytic wall enzymes in bacteria, causing bacteriolysis and tissue damage; and polycations and nuclear histones as potential virulence factors and as markers of sepsis, septic shock, disseminated intravasclar coagulopathy, acute lung injury, pancreatitis, trauma, and other additional clinical disorders...
2017: Journal of Inflammation Research
https://www.readbyqxmd.com/read/28198620/complexing-cations-by-polyethylene-oxide-binding-site-and-binding-mode
#3
Yuan Fang, Marianne Giesecke, Istvan Furo
The binding in methanol of K+ and Ba2+ cations to short polyethyleneoxide (PEO) chains with ca 4-25 monomeric units was studied via determining the effective charge of the polymer by a combination of electrophoretic NMR (eNMR) and diffusion NMR experiments. These cations were previously found to bind on similar strong manner to long PEO chains. In addition, 1H chemical shift and longitudinal spin relaxation rate changes upon binding were quantified. For both systems, binding was stronger for the short chains than that for longer chains that is attributed mainly to interactions between bound ions...
February 15, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28197596/amphiphilic-polymers-formed-from-ring-opening-polymerization-a-strategy-for-the-enhancement-of-gene-delivery
#4
Yi-Mei Zhang, Zheng Huang, Ji Zhang, Wan-Xia Wu, Yan-Hong Liu, Xiao-Qi Yu
Cationic liposomes and polymers are both important candidates for use as non-viral gene vectors. However, both of them have special shortcomings and application limits. This work is devoted to the combination of advantages of liposomes and polymers. The ring-opening polymerization strategy was used for the preparation of amphiphilic polymers from cyclen-based cationic small lipids. The non-hydrophobic polymer and the corresponding lipids were also prepared for performing structure-activity relationship studies...
February 15, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28193540/unusual-behaviour-induced-by-phase-separation-in-hydrogel-microspheres
#5
C L Heaysman, G J Phillips, A W Lloyd, A L Lewis
: Hydrogel microspheres with the capability to interact with charged species such as various drugs by ion-exchange processes are useful in a variety of biomedical applications. Such systems have been developed to allow active loading of the microsphere with chemotherapeutic agents in the hospital pharmacy for subsequent locoregional therapy of tumours in the liver by drug-eluting bead chemoembolization (DEB-TACE). A variety of microspherical embolisation systems have been described, all based upon hydrogels bearing anionic functionalities to allow interaction with cationically charged drugs...
February 10, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28193028/functionalized-cycloolefin-polymer-capillaries-for-open-tubular-ion-chromatography
#6
Weixiong Huang, Sasikarn Seetasang, Mohammadmehdi Azizi, Purnendu K Dasgupta
We describe novel cycloolefin polymer (COP)-based open tubular capillary ion exchange columns. COP capillaries (inner diameter of 19-28 μm) were successfully sulfonated at room temperature using a cocktail of ClSO3H (85-95% w/w) and HOAc or H2SO4. The cation exchange capacity is controlled by the sulfonation time and the sulfonation solution composition and can be as high as 300 pequiv/mm(2). Following sulfonation, the capillaries were coated with 65-nm-diameter anion exchanger (AEX) latex nanoparticles that attach electrostatically...
December 20, 2016: Analytical Chemistry
https://www.readbyqxmd.com/read/28192665/n-spirocyclic-quaternary-ammonium-ionenes-for-anion-exchange-membranes
#7
Thanh Huong Pham, Joel S Olsson, Patric Jannasch
The development of cationic polymers for anion-exchange membranes (AEMs) with high alkaline stability and conductivity is a considerable challenge in materials chemistry. In response, we here present the synthesis and properties of N-spirocyclic quaternary ammonium ionenes (spiro-ionenes) containing 5- and 6-membered rings fused by central nitrogen cations. High-molecular weight and film-forming spiro-ionenes are successfully synthesized in cyclo-polycondensations of tetrakis(bromomethyl)benzene and dipiperidines under mild conditions...
February 17, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28186520/quantifying-and-controlling-the-cation-uptake-upon-hydrated-ionic-liquid-induced-swelling-of-polyelectrolyte-multilayers
#8
N Parveen, M Schönhoff
Controlling the uptake of specific ions in polyelectrolyte multilayers is of interest for various fields of application. Here, we quantify the amount of cation of an ionic liquid, namely 1,3-bis(cyanomethyl)imidazolium chloride, incorporated into polyelectrolyte multilayers upon contact with an ionic liquid solution. The ion partition equilibrium is determined depending on concentration in solution, employing attenuated total reflection infrared spectroscopy. Generating an excess charge in multilayers by post-preparative manipulation of their charge balance, one can control the incorporated amount...
February 10, 2017: Soft Matter
https://www.readbyqxmd.com/read/28183180/regulation-mechanism-of-salt-ions-for-superlubricity-of-hydrophilic-polymer-cross-linked-networks-on-ti6al4v
#9
Caixia Zhang, Yuhong Liu, Zhifeng Liu, Hongyu Zhang, Qiang Cheng, Congbin Yang
Poly (vinylphosphonic acid)(PVPA) cross-linked networks on Ti6Al4V show superlubricity behavior when sliding against polytetrafluoroethylene (PTFE) in water-based lubricants. The superlubricity can occur, but only with the existence of salt ions in the polymer cross-linked networks. This is different from the phenomenon in most polymer brushes. An investigation into the mechanism revealed that cations and anions in the lubricants worked together to yield the superlubricity even in harsh conditions. It is proposed that the preferential interactions of cations with PVPA molecules rather than water molecules are the main reason for the superlubricity in water-based lubricants...
February 10, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28181720/organic-bioelectronics-in-medicine
#10
S Löffler, K Melican, K P R Nilsson, A Richter-Dahlfors
A major challenge in the growing field of bioelectronic medicine is the development of tissue interface technologies promoting device integration with biological tissues. Materials based on organic bioelectronics show great promise due to a unique combination of electronic and ionic conductivity properties. In this review, we outline exciting developments in the field of organic bioelectronics and demonstrate the medical importance of these active, electronically controllable materials. Importantly, organic bioelectronics offer a means to control cell-surface attachment as required for many device-tissue applications...
February 9, 2017: Journal of Internal Medicine
https://www.readbyqxmd.com/read/28181619/phosphatase-triggered-cell-selective-release-of-a-pt-iv-backboned-prodrug-like-polymer-for-an-improved-therapeutic-index
#11
Shao-Lu Li, Yingqin Hou, Yali Hu, Jin Yu, Wei Wei, Hua Lu
We describe here the synthesis and cell-selective delivery of a cationic Pt(iv)-backboned prodrug-like polymer P(DSP-DAEP). P(DSP-DAEP) features excellent aqueous solubility, unusually high (44.5%) drug loading, can be rapidly reduced to release the active cisplatin, and is more potent than its small molecular Pt(iv) precursor DSP. P(DSP-DAEP) can be formulated with an oppositely charged methoxyl poly(ethylene glycol)-block-poly(l-phosphotyrosine) (mPEG-b-PpY) to afford a polyion micelle (Pt-PIC) by taking advantage of polyelectrolyte coacervation...
February 9, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28181193/history-of-polymeric-gene-delivery-systems
#12
REVIEW
Peng Zhang, Ernst Wagner
As an option for genetic disease treatment and an alternative for traditional cancer chemotherapy, gene therapy achieves significant attention. Nucleic acid delivery, however, remains a main challenge in human gene therapy. Polymer-based delivery systems offer a safer and promising route for therapeutic gene delivery. Over the past five decades, various cationic polymers have been optimized for increasingly effective nucleic acid transfer. This resulted in a chemical evolution of cationic polymers from the first-generation polycations towards bioinspired multifunctional sequence-defined polymers and nanocomposites...
April 2017: Topics in Current Chemistry (Journal)
https://www.readbyqxmd.com/read/28177587/continuous-microfluidic-assembly-of-biodegradable-poly-beta-amino-ester-dna-nanoparticles-for-enhanced-gene-delivery
#13
David R Wilson, Arman Mosenia, Mark P Suprenant, Rahul Upadhya, Denis Routkevitch, Randall A Meyer, Alfredo Quinones-Hinojosa, Jordan J Green
Translation of biomaterial-based nanoparticle formulations to the clinic faces significant challenges including efficacy, safety, consistency and scale-up of manufacturing, and stability during long-term storage. Continuous microfluidic fabrication of polymeric nanoparticles has the potential to alleviate the challenges associated with manufacture, while offering a scalable solution for clinical level production. Poly(beta-amino esters) (PBAE)s are a class of biodegradable cationic polymers that self-assemble with anionic plasmid DNA to form polyplex nanoparticles that have been shown to be effective for transfecting cancer cells specifically in vitro and in vivo...
February 8, 2017: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28176676/hydrolyzed-hexagonal-boron-nitride-polymer-nanocomposites-for-transparent-gas-barrier-film
#14
Tan Young Kim, Eun Ho Song, Byung Hyun Kang, Se Jung Kim, Yun-Hi Lee, Byeong-Kwon Ju
A flexible thin gas barrier film formed by layer-by-layer (LBL) assembly has been studied. We propose for the first time that hexagonal boron nitride (h-BN) can be used in LBL assembly. When dispersed in water through sonication-assisted hydrolysis, h-BN develops hydroxyl groups that electrostatically couple with the cationic polymer polydiallyldimethylammonium chloride (PDDA). This process produces hydroxyl-functional h-BN /PDDA nanocomposites. The nanocomposites exhibit well exfoliated and highly ordered h-BN nanosheets, which results in an extremely high visual clarity, with an average transmittance of 99% in the visible spectrum...
February 8, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28170266/piezochromic-topology-switch-in-a-coordination-polymer
#15
Michał Andrzejewski, Andrzej Katrusiak
Abrupt color changes coupled to a giant strain in the crystal of coordination polymer CoCl2bpp (bpp=1,3-bis(4-pyridyl)propane) mark piezochromic reversible transformations at 1.93 GPa from blue phase α to green phase β and at 2.39 GPa to colorless phase γ. The clearly visible shape and color changes are ideal for calibrating discrete pressure magnitudes associated with these phase transitions. The crystal spectra have been measured and the structures have been determined in-situ under pressure in a diamond-anvil cell...
February 7, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28169516/preparation-of-porous-polysaccharides-templated-by-coordination-polymer-with-three-dimensional-nanochannels
#16
Yuichiro Kobayashi, Kayako Honjo, Susumu Kitagawa, Takashi Uemura
Polymerization of monosaccharide monomers usually suffers from the production of polysaccharides with ill-defined structures because of the uncontrolled random reactions among many reactive hydroxyl groups on saccharide monomers. In particular, rational synthesis of polysaccharides with porosity approximating molecular dimensions is still in its infancy, despite their use-fulness as drug carriers. Here, we disclose an efficient synthetic methodology for the preparation of polysaccharides with con-trollable mesoporosity in the structure, utilizing porous coordination polymers (PCPs) as templates...
February 7, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28169476/metallo-polymer-chain-extension-controls-the-morphology-and-release-kinetics-of-microparticles-composed-of-terpyridine-capped-polylactides-and-their-stereocomplexes
#17
Marek Brzeziński, Anna Kacprzak, Marcelo Calderón, Sebastian Seiffert
Control over morphology and porosity of supramolecular complexed polylactide (PLA) microparticles can be achieved by manipulation of the supramolecular interactions between their constituent polymeric building blocks. It is expected that such modular systems are ideal candidates to serve as degradable delivery carriers. In view of this goal, this study reports about a modular fabrication of biodegradable microparticles from terpyridine (TPy) and bisterpyridine (bisTPy) end-functionalized PLAs that can be transiently extended by chain association through differently strong complexation to three metal cations: Ni(2+) , Co(2+) , or Fe(2+) ...
February 7, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/28165737/phosphonium-functionalized-polymer-micelles-with-intrinsic-antibacterial-activity
#18
Benjamin Hisey, Paul J Ragogna, Elizabeth R Gillies
New approaches to treat bacterial infections are badly needed to address the increasing problem of antibiotic-resistance. This study explores phosphonium-functionalized block copolymer micelles as intrinsically antibacterial polymer assemblies. Phosphonium cations with varying alkyl lengths were conjugated to the terminus of a poly(ethylene oxide)-polycaprolactone block copolymer and the phosphonium-functionalized block copolymers were self-assembled to form micelles in aqueous solution. The size, morphology, and ζ-potential of the assemblies were studied and their abilities to kill Escherichia coli and Staphylococcus aureus were evaluated...
February 6, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28162250/effects-of-anthropogenic-surfactants-on-the-conversion-of-marine-dissolved-organic-carbon-and-microgels
#19
Ruei-Feng Shiu, Chon-Lin Lee
The possible impact of three types of anthropogenic surfactants on the ability of marine dissolved organic carbon (DOC) to form self-assembled microgels was evaluated. The behavior of existing native microgels was also examined in the presence of surfactants. These results reveal that the release of surfactants even at low concentrations into the aquatic environment could effectively hinder the self-assembly of DOC polymers. The extent of the size reduction had the following order: anionic, cationic, and non-ionic...
February 2, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28159519/intracellular-responsive-dual-delivery-by-endosomolytic-polyplexes-carrying-dna-anchored-porous-silicon-nanoparticles
#20
Mohammad-Ali Shahbazi, Patrick Vingadas Almeida, Alexandra Correia, Barbara Herranz-Blanco, Neha Shrestha, Ermei Mäkilä, Jarno Salonen, Jouni Hirvonen, Hélder A Santos
Bioresponsive cytosolic nanobased multidelivery has been emerging as an enormously challenging novel concept due to the intrinsic protective barriers of the cells and hardly controllable performances of nanomaterials. Here, we present a new paradigm to advance nano-in-nano integration technology amenable to create multifunctional nanovehicles showing considerable promise to overcome restrictions of intracellular delivery, solve impediments of endosomal localization and aid effectual tracking of nanoparticles...
February 1, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
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