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Cationic polymers

Guido H Clever, Philip Punt
Compounds featuring one-dimensional regular arrangements of stacked metal complexes and alternating [cation-anion]∞ sequences have raised considerable interest owing to their peculiar electronic and optical properties as well as guest inclusion capabilities. While traditional ways to realize these structural motifs rely on crystalline compounds, exclusively existing in the solid state, recent progress in the area of metal-mediated supramolecular self-assembly allows for the rational synthesis of structurally well-defined short stretches of stacked metal complexes and cation-anion arrangements...
August 17, 2017: Accounts of Chemical Research
Chen Shen, Jun Li, Yi Zhang, Yuce Li, Guanxin Shen, Jintao Zhu, Juan Tao
Vaccines have shown great success in treating and preventing tumors and infections, while adjuvants are always demanded to ensure potent immune responses. Polyethylenimine (PEI), as one of the well-studied cationic polymers, has been used as a transfection reagent for decades. However, increasing evidence has shown that PEI-based particles are also capable of acting as adjuvants. In this paper, we briefly review the physicochemical properties and the broad applications of PEI in different fields, and elaborate on the intracellular processes of PEI-based vaccines...
2017: International Journal of Nanomedicine
Aubin Moutal, Xiaofang Yang, Wennan Li, Kerry B Gilbraith, Shizhen Luo, Song Cai, Liberty François-Moutal, Lindsey A Chew, Seul Ki Yeon, Shreya S Bellampalli, Chaoling Qu, Jennifer Y Xie, Mohab M Ibrahim, May Khanna, Ki Duk Park, Frank Porreca, Rajesh Khanna
Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disease linked to mutations of the Nf1 gene. Patients with NF1 commonly experience severe pain. Studies on mice with Nf1 haploinsufficiency have been instructive in identifying sensitization of ion channels as a possible cause underlying the heightened pain suffered by patients with NF1. However, behavioral assessments of Nf1 mice have led to uncertain conclusions about the potential causal role of Nf1 in pain. We used the clustered regularly interspaced short palindromic repeats (CRISPR)-associated 9 (CRISPR/Cas9) genome editing system to create and mechanistically characterize a novel rat model of NF1-related pain...
July 3, 2017: Pain
Aneta Idec, Miłosz Pawlicki, Lechosław Latos-Grażyński
A diamagnetic ruthenium(II) complex of 5,10,15,20-tetraphenyl-p-benziporphyrin [Ru(II)(p-BzP)(CO)Cl] was obtained via the insertion of ruthenium into p-benziporphyrin using triruthenium(0) dodecacarbonyl [Ru3(CO)12] as the metal source. The procedure applying dichloro(cycloocta-1,5-diene)ruthenium(II) (polymer, [Ru(COD)Cl2]n) afforded the paramagnetic six-coordinate ruthenium(III) p-benziporphyrin [Ru(III)(p-BzP)Cl2]. As shown by X-ray crystallography, the p-phenylene ring in both complexes is sharply tilted out of the N3 plane, as reflected by the respective N3 (pyrrole)-C6 (p-phenylene) dihedral angle [Ru(II)(p-BzP)(CO)Cl, 52...
August 15, 2017: Inorganic Chemistry
Min Ling, Wenjun Yan, Ayako Kawase, Hui Zhao, Yanbao Fu, Vincent S Battaglia, Gao Liu
Cationic polymer can capture polysulfide ions and inhibit polysulfide shuttle effect in lithium sulfur (Li-S) rechargeable batteries, enhancing the Li-S battery cycling performance. The cationic poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino) propyl]urea] quaternized (PQ) with a high density quaternary ammonium cations can trap the lithium polysulfide through the electrostatic attraction between positively charged quaternary ammonium (R4N+) and negatively charged polysulfide (Sx2-). PQ binder based sulfur electrodes deliver much higher capacity and provide better stability than traditional polyvinylidene fluoride (PVDF) binder based electrodes in Li-S cells...
August 15, 2017: ACS Applied Materials & Interfaces
Julie R McGettrick, Christopher P Palmer
Capillary electrophoresis and electrokinetic chromatography are typically carried out in unmodified fused silica capillaries under conditions that result in a strong negative zeta potential at the capillary wall and a robust cathodic electroosmotic flow. Modification of the capillary wall to reverse the zeta potential and mask silanol sites can improve separation performance by reducing or eliminating analyte adsorption, and is essential when conducting electrokinetic chromatography separations with cationic latex nanoparticle pseudo-stationary phases...
August 12, 2017: Journal of Separation Science
Marleen Wilde, Rebecca J Green, Michael R Sanders, Francesca Greco
Understanding how polymers interact with biological membranes is important for the development of polymer based therapeutics and wider biomedical applications. Here, biophysical methods (surface pressure measurements, external reflection FTIR) have been used to investigate the interaction between PAMAM dendrimers (Generation 5 or 4.5) and anionic (DPPG) or zwitterionic (DPPC) model membranes. We observed a concentration-dependent binding behaviour of both PAMAM species to both model membranes; however, equivalent levels of penetration into DPPC monolayers required approximately 10-fold higher dendrimer concentrations than for penetration into DPPG monolayers...
August 10, 2017: Journal of Drug Targeting
Vaishali Sethi, Jayanti Mishra, Arpan Bhattacharyya, Debasis Sen, Ashok K Ganguli
Designing nanostructures of desired morphology calls for development of new synthetic protocols to stimulate structural alterations in templates, modulating the architecture of nano-metric structures. The present study is an endeavor to investigate structural modifications in reverse micellar nanotemplates of a cationic surfactant system, CTAB/butanol/water/isooctane, as a function of hydrotrope concentration (sodium salicylate) and amount of water loading, Wx, in the micellar pool by synchrotron small-angle X-ray scattering...
August 9, 2017: Physical Chemistry Chemical Physics: PCCP
Romain Dubey, Robert J Comito, Zhenwei Wu, Guanghui Zhang, Adam J Rieth, Christopher H Hendon, Jeffrey T Miller, Mircea Dinca
Molecular catalysts offer tremendous advantages for stereoselective polymerization because their activity and selectivity can be optimized and understood mechanistically using the familiar tools of organometallic chemistry. Yet, this exquisite control over selectivity comes at an operational price that is generally not justifiable for the large-scale manufacture of polyfolefins. In this report we identify Co-MFU-4l, prepared by cation exchange in a metal-organic framework, as a solid catalyst for the polymerization of 1,3-butadiene with high stereoselectivity (>99 % 1,4-cis)...
August 7, 2017: Journal of the American Chemical Society
Ying Zeng, Rui-Kang Huang, Zi-Yi Du, Chun-Ting He, Wei-Xiong Zhang, Xiao-Ming Chen
Two new double perovskite-like azido coordination polymers with trimethylammonium as the guest cation, namely, (Me3NH)2[CrNa(N3)6] and (Me3NH)2[CrK(N3)6], have been prepared. The molecular dynamics for both compounds are investigated and are clearly uncovered by the first-principles molecular dynamics simulation and the significant dielectric relaxation. Structural analyses of these compounds in combination with their analogue (Me3NH)[Mn(N3)3] reveal that the guest trimethylammonium has flexible structural adaptability, especially with a variety of disordered distributions, to match the different symmetries of varied metal-azido frameworks...
August 7, 2017: Inorganic Chemistry
Priya S S, Rekha M R
Thiolated cationic pullulan was synthesized by conjugating pullulan with polyethyleneimine (PEI) and mercaptosuccinic acid (MSA). The formed conjugate was oxidized to obtain disulfide linked cationic pullulan (PPMSS). PPMSS exhibited good buffering capacity and nanoplexes formulated were of size less than 150nm. Nanoplexes formed with PPMSS are redox sensitive and susceptible to reductive cleavage by dithiothreitol (DTT) ensuring the intracellular release of DNA. In vitro, cytotoxic evaluation studies of polymers in C6 cell lines established its non-toxic nature...
August 2, 2017: International Journal of Pharmaceutics
Wenqian Chen, Naoki Ogiwara, Kentaro Kadota, Kitt Panyarat, Susumu Kitagawa, Satoshi Horike
We synthesized a coordination polymer, [EtMeIm][Cu(bpy)(Me2PO4)3], containing an anionic 1-D chain and an ethyl methyl imidazolium cation. The organic cations show fast transport behavior, and the observed ion conductivity is 1.4 × 10(-3) S cm(-1) at 110 °C. The stability and structure of the material were confirmed by DSC, X-ray adsorption, and long-term AC impedance spectroscopy.
August 4, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Shahin Homaeigohar, Ahnaf Usman Zillohu, Ramzy Abdelaziz, Mehdi Keshavarz Hedayati, Mady Elbahri
In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES) for removal of methylene blue (MB) dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption of cationic MB molecules. As an extra challenge, to augment the adsorbent's properties in terms of adsorption capacity in neutral and acidic conditions and thermal stability, vanadium pentoxide (V₂O₅) nanoparticles were added to the nanofibers...
October 19, 2016: Materials
Chuanliang Zhao, Huaili Zheng, Li Feng, Yili Wang, Yongzhi Liu, Bingzhi Liu, Badradine Zakaria Djibrine
Cationic polyacrylamides have been employed widely to improve sludge dewatering performance, but the cationic units are randomly distributed in the molecular chain, which restricts the further enhancement of dewaterability. Common template technology to prepare block copolymers requiring a huge number of templates reduces the polymer purity and molecular weight. Here, we adopted the surface-active monomer benzyl dimethyl 2-(methacryloyloxy)ethyl ammonium chloride (BDMDAC) to synthesize cationic microblocky polyacrylamide initiated by ultrasound...
March 13, 2017: Materials
Yogeswaran Umasankar, Bal-Ram Adhikari, Aicheng Chen
An efficient approach for immobilizing alcohol dehydrogenase (ADH) while enhancing its electron transfer ability has been developed using poly(2-(trimethylamino)ethyl methacrylate) (MADQUAT) cationic polymer and carbon nanoscaffolds. The carbon nanoscaffolds were comprised of single-walled carbon nanotubes (SWCNTs) wrapped with reduced graphene oxide (rGO). The ADH entrapped within the MADQUAT that was present on the carbon nanoscaffolds exhibited a high electron exchange capability with the electrode through its cofactor β-nicotinamide adenine dinucleotide hydrate and β-nicotinamide adenine dinucleotide reduced disodium salt hydrate (NAD(+)/NADH) redox reaction...
July 26, 2017: Bioelectrochemistry
Xavier Banquy, Frantz Le Dévédec, Hsiu-Wei Cheng, Jimmy Faivre, Julian X X Zhu, Markus Valtiner
We present a study focused on characterizing the interaction forces between mica surfaces across solutions containing star-shaped polymers with cationic ends. Using the surface forces apparatus, we show that the interaction forces in pure water between surfaces covered with the polymers can be adequately described by the dendronized brush model. In that framework, our experimental data suggest that the number of branches adsorbed at the surface decreases as the concentration of polymer in the adsorbing solution increases...
August 11, 2017: ACS Applied Materials & Interfaces
Luca Pellegrino, Rossana Cocchiola, Iolanda Francolini, Mariangela Lopreiato, Antonella Piozzi, Robertino Zanoni, Anna Scotto d'Abusco, Andrea Martinelli
Biocompatible and degradable poly(α-hydroxy acids) are one of the most widely used materials in scaffolds for tissue engineering. Nevertheless, they often need surface modification to improve interaction with cells. Aminolysis is a common method to increase the polymer hydrophilicity and to introduce surface functional groups, able to covalently link or absorb, through electrostatic interaction, bioactive molecules or macromolecules. For this purpose, multi-functional amines, such as diethylenediamine or hexamethylenediamine are used...
July 23, 2017: Colloids and Surfaces. B, Biointerfaces
Quentin Duez, Fabien Chirot, Romain Liénard, Thomas Josse, ChangMin Choi, Olivier Coulembier, Philippe Dugourd, Jérôme Cornil, Pascal Gerbaux, Julien De Winter
One of the main issues when using traveling wave ion mobility spectrometry (TWIMS) for the determination of collisional cross-section (CCS) concerns the need for a robust calibration procedure built from referent ions of known CCS. Here, we implement synthetic polymer ions as CCS calibrants in positive ion mode. Based on their intrinsic polydispersities, polymers offer in a single sample the opportunity to generate, upon electrospray ionization, numerous ions covering a broad mass range and a large CCS window for different charge states at a time...
July 31, 2017: Journal of the American Society for Mass Spectrometry
Mengwei Han, Rosa M Espinosa-Marzal
We have measured forces between mica surfaces coated with a poly(ethylene glycol) (PEG) brush solvated by a vacuum dry ionic liquid, 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide, with a surface forces apparatus. At high grafting density, the solvation mediated by the ionic liquid causes the brush to stretch twice as much as in water. Modeling of the steric repulsion indicates that PEG behaves as a polyelectrolyte; the hydrogen bonding between ethylene glycol and the imidazolium cation seems to effectively charge the polymer brush, which justifies the strong stretching...
July 31, 2017: Journal of Physical Chemistry Letters
Yunjiang Jiang, Wan Zheng, Liangju Kuang, Hairong Ma, Hongjun Liang
The prevalent wisdom on developing membrane active antimicrobials (MAAs) is to seek a delicate, yet unquantified cationic-hydrophobic balance. Inspired by phages that use nanostructured protein devices to invade bacteria efficiently and selectively, we study here the antibiotic role of nanostructures by designing spherical and rod-like polymer molecular brushes (PMBs) that mimic the two basic structural motifs of bacteriophages. Three model PMBs with different well-defined geometries consisting of multiple identical copies of densely packed poly(4-vinyl-N-methylpyridine iodide) branches are synthesized by controlled/"living" polymerization, reminiscence of the viral structural motifs comprised of multiple copies of protein subunits...
July 31, 2017: ACS Infectious Diseases
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