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Cationic polymers

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https://www.readbyqxmd.com/read/29155787/synthesis-of-core-shell-lanthanide-doped-upconversion-nanocrystals-for-cellular-applications
#1
Xiangzhao Ai, Linna Lyu, Jing Mu, Ming Hu, Zhimin Wang, Bengang Xing
Lanthanide-doped upconversion nanocrystals (UCNs) have attracted much attention in recent years based on their promising and controllable optical properties, which allow for the absorption of near-infrared (NIR) light and can subsequently convert it into multiplexed emissions that span over a broad range of regions from the UV to the visible to the NIR. This article presents detailed experimental procedures for high-temperature co-precipitation synthesis of core-shell UCNs that incorporate different lanthanide ions into nanocrystals for efficiently converting deep-tissue penetrable NIR excitation (808 nm) into a strong blue emission at 480 nm...
November 10, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29152372/synthesis-and-crystal-structure-of-a-two-dimensional-co-ii-coordination-polymer-poly-%C3%AE-3-3-carb-oxy-benzoato-%C3%AE-2-5-pyridin-4-yl-1h-2-h-3-3-bi-1-2-4-triazole-cobalt-ii
#2
Chao-Jun Du, Xiao-Na Zhao, Bao-Yong Chen
In the title compound, [Co(C8H5O4)(C9H6N7)] n , the divalent Co(II) atom is six-coordinated to three N atoms from two symmetrical 5-(pyridin-4-yl)-1H,2'H-3,3'-bi[1,2,4-triazole] (H2pyttz) ligands and three O atoms from three symmetrical 3-carb-oxy-benzoate (Hbdic) ligands, leading to a distorted {CoN3O3} octa-hedral coordination environment. Two Co(II) cations are linked by four bridging carboxyl-ate groups to generate a dinuclear [Co2(CO2)4] unit. The dinuclear units are further connected into a chain along [010] via the Hbdic ligands...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29152368/synthesis-crystal-structure-and-hirshfeld-surface-analysis-of-a-polymeric-bis-muthate-iii-halide-complex-c6h6n3-2-bicl5-%C3%A2-2h2o
#3
Chaima Boukoum, Zouhaier Aloui, Valeria Ferretti, Sonia Abid
The synthesis and the crystal structure of a new halide-bridged polymer, namely catena-poly[bis-(1,2,3-benzotriazolium) [[tetra-chlorido-bis-muth(III)]-μ-chlorido] dihydrate], {(C6H6N3)2[BiCl5]·2H2O} n are reported. The structure comprises polyanionic zigzag chains of formula [(BiCl5)(2-)] n running along the c-axis direction. The 1,2,3-benzotriazolium cations are linked between these polymer chains, via the water mol-ecules, giving rise to left- and right-handed helical chains. Hirshfeld surface analysis and fingerprint plots were used to decode the inter-molecular inter-actions in the crystal network and determine the contribution of the component units for the construction of the three-dimensional architecture...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29152354/crystal-structure-of-a-looped-chain-co-ii-coordination-polymer-catena-poly-bis-nitrato-%C3%AE%C2%BAo-cobalt-ii-bis-%C3%AE-bis-pyridin-3-ylmeth-yl-sulfane-%C3%AE%C2%BA-2-n-n
#4
Suk-Hee Moon, Joobeom Seo, Ki-Min Park
The asymmetric unit of the title compound, [Co(NO3)2(C12H12N2S)2] n , contains a bis-(pyridin-3-ylmeth-yl)sulfane (L) ligand, an NO3(-) anion and half a Co(II) cation, which lies on an inversion centre. The Co(II) cation is six-coordinated, being bound to four pyridine N atoms from four symmetry-related L ligands. The remaining coordination sites are occupied by two O atoms from two symmetry-related nitrate anions in a monodentate manner. Thus, the Co(II) centre adopts a distorted octa-hedral geometry. Two symmetry-related L ligands are connected by two symmetry-related Co(II) cations, forming a 20-membered cyclic dimer, in which the Co(II) atoms are separated by 10...
November 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/29147695/synthesis-of-an-ethyleneimine-tetrahedral-dna-nanostructure-complex-and-its-potential-application-as-a-multi-functional-delivery-vehicle
#5
Taoran Tian, Tao Zhang, Tengfei Zhou, Shiyu Lin, Sirong Shi, Yunfeng Lin
Nowadays, DNA nanostructures are extensively researched for their biocompatibility, editable functionality, and structural stability. Tetrahedral DNA nanostructures (TDNs), widely known for their membrane permeability, are regarded as potential candidates for drug delivery. However, the stability and membrane permeability of TDNs call for further enhancement if in vivo usage is ascribed. To overcome the drawbacks of TDNs, ethylene imine (PEI, 25 kDa, branched)-a classic cationic polymer in the field of gene delivery-was applied...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29147533/what-is-the-fundamental-ion-specific-series-for-anions-and-cations-ion-specificity-in-standard-partial-molar-volumes-of-electrolytes-and-electrostriction-in-water-and-non-aqueous-solvents
#6
Virginia Mazzini, Vincent S J Craig
The importance of electrolyte solutions cannot be overstated. Beyond the ionic strength of electrolyte solutions the specific nature of the ions present is vital in controlling a host of properties. Therefore ion specificity is fundamentally important in physical chemistry, engineering and biology. The observation that the strengths of the effect of ions often follows well established series suggests that a single predictive and quantitative description of specific-ion effects covering a wide range of systems is possible...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29147525/multi-component-hybrid-hydrogels-understanding-the-extent-of-orthogonal-assembly-and-its-impact-on-controlled-release
#7
Vânia M P Vieira, Laura L Hay, David K Smith
This paper reports self-assembled multi-component hybrid hydrogels including a range of nanoscale systems and characterizes the extent to which each component maintains its own unique functionality, demonstrating that multi-functionality can be achieved by simply mixing carefully-chosen constituents. Specifically, the individual components are: (i) pH-activated low-molecular-weight gelator (LMWG) 1,3;2,4-dibenzylidenesorbitol-4',4''-dicarboxylic acid (DBS-COOH), (ii) thermally-activated polymer gelator (PG) agarose, (iii) anionic biopolymer heparin, and (iv) cationic self-assembled multivalent (SAMul) micelles capable of binding heparin...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29144306/characterization-of-a-hybrid-polyacrylamide-and-its-flocculation-properties-in-cyanide-tailing-suspensions
#8
Ya Liu, Cuicui Lv, Jian Ding, Peng Qian, Yang Yu, Shufeng Ye, Yunfa Chen
An inorganic-organic hybrid flocculant Al(OH)3-polyacrylamide (Al-PAM) with narrow molecular weight distribution was synthesized using inverse microemulsion polymerization. The hybrid polymer Al-PAM was characterized by Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and scanning electron microscopy, and it was found that it had a 'star-like' structure in which Al(OH)3 colloidal particles acted as cores linking PAM chains. The properties of Al-PAM were investigated in flocculating 10 wt% cyanide tailing suspensions...
November 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29143829/spectral-properties-of-ionic-benzotristhiazole-based-donor-acceptor-nlo-phores-in-polymer-matrices-and-their-one-and-two-photon-cellular-imaging-ability
#9
M Danko, P Hrdlovič, A Martinická, A Benda, M Cigáň
A series of ionic benzotristhiazolium (BTT) push-pull chromophores, with different nitrogen donor groups and different lengths of conjugated bridges, was successfully doped in polar polymer matrices (PVC and PSS). The spectral (photophysical) properties of their low concentration thin polymeric films are compared with those in solution and are discussed in terms of matrix polarity/viscosity influence, specific polymer-chromophore interaction, structure-spectral property relationship and Twisted Intramolecular Charge-Transfer (TICT) state formation...
November 16, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/29137172/fluorescent-magnetopolymersomes-a-theranostic-platform-to-track-intracellular-delivery
#10
Oliver Bixner, Noga Gal, Christoph Zaba, Andrea Scheberl, Erik Reimhult
We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species...
November 13, 2017: Materials
https://www.readbyqxmd.com/read/29135264/peptide-based-polymer-polyoxometalate-supramolecular-structure-with-differed-antimicrobial-mechanism
#11
Lakshmi Priya Datta, Riya Mukherjee, Subharanjan Biswas, Tapan Kumar Das
Because of the increasing prevalence of multi-drug resistance feature, several investigations have been so far reported regarding the antibiotic alternative supramolecular bioactive agents made of hybrid assemblies. In this regard, it is well established that combinational therapy inherited by assembled supramolecular structures can improve the bioactivity to some extent but their mode of actions have not been studied in details. We provide the first direct evidence that the improved mechanism of action of antimicrobial supra-amphiphilic nanocomposites differ largely from their parent antimicrobial peptide based polymers...
November 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29134801/adsorbed-polyzwitterion-copolymer-layers-designed-for-protein-repellency-and-interfacial-retention
#12
S Kalasin, R A Letteri, T Emrick, M M Santore
Poly(2-methacryloyloxyethyl phosphorylcholine) (pMPC), when end-tethered to surfaces by the adsorption of copolymeric cationic segments, forms adsorbed layers that substantially reduce protein adsorption. This study examined variations in the molecular architecture of copolymers containing cationic poly(trimethylammonium ethyl methacrylate (pTMAEMA) anchor blocks that adsorbed strongly to negative surfaces. With appropriate copolymer design, the pTMAEMA blocks were shielded, by pMPC tethers, from solution-phase proteins...
November 14, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/29134216/multiple-interaction-regulated-phase-transition-behavior-of-thermo-responsive-copolymers-containing-cationic-poly-ionic-liquid-s
#13
Yingna Zhang, Hui Tang, Peiyi Wu
The effect of multiple interactions including anion-macromolecule interaction, water-mediated ion-macromolecule interaction and hydrophobic interaction on the phase transition behaviors of random copolymers P(OEGMA-co-BVIm[X]) comprising oligo(ethylene glycol)methacrylate (OEGMA) and imidazolium-based ionic liquids is investigated in the present study. Temperature-variable (1)H NMR and FT-IR investigations demonstrated that the hydration of CH2 side chains in P(OEGMA-co-BVIm[SCN]) was enhanced due to the anion-dipole interaction between a chaotropic anion SCN(-) and CH2 groups, and dehydration of C[double bond, length as m-dash]O groups served as the driving force of phase transition...
November 14, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29133981/electrostatic-interactions-between-polyglutamic-acid-and-polylysine-yields-stable-polyion-complex-micelles-for-deoxypodophyllotoxin-delivery
#14
Yutong Wang, Liping Huang, Yan Shen, Lidan Tang, Runing Sun, Di Shi, Thomas J Webster, Jiasheng Tu, Chunmeng Sun
To achieve enhanced physical stability of poly(ethylene glycol)-poly(d,l-lactide) polymeric micelles (PEG-PDLLA PMs), a mixture of methoxy PEG-PDLLA-polyglutamate (mPEG-PDLLA-PLG) and mPEG-PDLLA-poly(l-lysine) (mPEG-PDLLA-PLL) copolymers was applied to self-assembled stable micelles with polyion-stabilized cores. Prior to micelle preparation, the synthetic copolymers were characterized by (1)H-nuclear magnetic resonance (NMR) and infrared spectroscopy (IR), and their molecular weights were calculated by (1)H-NMR and gel permeation chromatography (GPC)...
2017: International Journal of Nanomedicine
https://www.readbyqxmd.com/read/29131611/synthesis-and-in-vitro-evaluation-of-monodisperse-amino-functional-polyester-dendrimers-with-rapid-degradability-and-antibacterial-properties
#15
Patrik Stenström, Erik Hjort, Yuning Zhang, Oliver C J Andrén, Simon Guette-Marquet, Marianne Schultzberg, Michael Malkoch
Amine functional polymers, especially cationically charged, are interesting biomacromolecules for several reasons including easy cell membrane entrance, their ability to escape endosomes through the proton sponge effect, spontaneous complexation and delivery of drugs and siRNA and simple functionalization in aqueous solutions. Dendrimers, a subclass of precision polymers, are monodisperse and exhibit a large and exact number of peripheral end groups in relation to their size and have shown promise in drug delivery, biomedical imaging and as anti-viral agents...
November 13, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29131607/carbon-papers-and-aerogels-based-on-graphene-layers-and-chitosan-direct-preparation-from-high-surface-area-graphite
#16
Vincenzina Barbera, Silvia Guerra, Luigi Brambilla, Mario Maggio, Andrea Serafini, Lucia Conzatti, Alessandra Vitale, Maurizio Galimberti
In this work, carbon papers and aerogels based on graphene layers and chitosan were prepared. They were obtained by mixing chitosan (CS) and a high surface area nanosized graphite (HSAG) in water in the presence of acetic acid. HSAG/CS water dispersions were stable for months. High resolution transmission electron microscopy revealed the presence of few graphene layers in water suspensions. Casting or lyophilization of such suspensions led to the preparation of carbon paper and aerogel respectively. In X-ray spectra of both aerogels and carbon paper, peaks due to regular stacks of graphene layers were not detected: graphene with unaltered sp(2) structure was obtained directly from graphite without the use of any chemical reaction...
November 13, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29129572/biocompatible-fluorinated-poly-%C3%AE-amino-ester-s-for-safe-and-efficient-gene-therapy
#17
Jia-Hui Gong, Yi Wang, Lei Xing, Peng-Fei Cui, Jian-Bin Qiao, Yu-Jing He, Hu-Lin Jiang
Cationic polymers have been widely used as one of the most promising non-viral vehicles for gene delivery due to their potential safety and ease of large-scale production. Here, we report the design and synthesis of a series of novel biodegradable fluorinated poly(β-amino ester)s (FPBAEs) by simple Michael-addition reaction as safe and efficient gene carrier. The results of transfection efficacy assay demonstrated the optimal FPBAE could mediated much higher GFP expression than the commercial transfection agents, polyethyleneimine (PEI, Mw = 25K) and Lipo 2000, as well as the non-fluorinated poly(β-amino ester)s (PBAE) on both HeLa and HEK-293T cell lines (higher than 70 and 90%, respectively), which was largely attributed to fluorination...
November 10, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/29127036/amphiphilic-poly-%C3%AE-glutamate-polymeric-micelles-for-systemic-administration-of-sirna-to-tumors
#18
Adva Krivitsky, Dina Polyak, Anna Scomparin, Shay Eliyahu, Paula Ofek, Galia Tiram, Hagar Kalinski, Sharon Avkin-Nachum, Natàlia Feiner Gracia, Lorenzo Albertazzi, Ronit Satchi-Fainaro
RNAi therapeutics carried a great promise to the area of personalized medicine: the ability to target "undruggable" oncogenic pathways. Nevertheless, their efficient tumor targeting via systemic administration had not been resolved yet. Amphiphilic alkylated poly(α)glutamate amine (APA) can serve as a cationic carrier to the negatively-charged oligonucleotides. APA polymers complexed with siRNA to form round-shaped, homogenous and reproducible nano-sized polyplexes bearing ~50nm size and slightly negative charge...
November 7, 2017: Nanomedicine: Nanotechnology, Biology, and Medicine
https://www.readbyqxmd.com/read/29125281/brush-like-cationic-polymers-with-low-charge-density-for-gene-delivery
#19
Jonathan O'Keeffe Ahern, Sigen A, Dezhong Zhou, Yongsheng Gao, Jing Lyu, Zhao Meng, Lara Cutlar, Luca Pierucci, Wenxin Wang
Using a combined synthesis approach comprising reversible addition fragmentation transfer (RAFT) polymerization and ring opening reaction (ROR), a series of poly glycidyl methacrylate (polyGMA) polymers were designed and synthesized for gene delivery. These polymers characterised by low cationic charge respective to established gene delivery vectors such as PEI were studied to further elucidate the key structure activity parameters which mediate efficient and biocompatible gene delivery. Compared to PEI these brush-like polymers facilitated markedly improved safety and gene delivery efficiency...
November 10, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29124707/uv-disinfection-of-wastewater-and-combined-sewer-overflows
#20
John Gibson, Jennifer Drake, Bryan Karney
Municipal wastewater contains bacteria, viruses, and other pathogens that adversely affect the environment, human health, and economic activity. One way to mitigate these effects is a final disinfection step using ultraviolet light (UVL). The advantages of UVL disinfection, when compared to the more traditional chlorine, include no chlorinated by-products, no chemical residual, and relatively compact size. The design of most UV reactors is complex. It involves lamp selection, power supply design, optics, and hydraulics...
2017: Advances in Experimental Medicine and Biology
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