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https://www.readbyqxmd.com/read/28441615/near-infrared-light-stimuli-responsive-synergistic-therapy-nanoplatforms-based-on-the-coordination-of-tellurium-containing-block-polymer-and-cisplatin-for-cancer-treatment
#1
Feng Li, Tianyu Li, Wei Cao, Lu Wang, Huaping Xu
Cisplatin (CDDP) has received worldwide approval for clinical use in the past decades. However, its development in cancer chemotherapy was overshadowed by severe side effects and drug resistance. Herein, we developed a CDDP drug delivery system with high encapsulation efficiency and near-infrared light stimuli-responsive drug release properties based on the coordination of novel tellurium-containing block polymer (PEG-PUTe-PEG) and CDDP. The nanocarriers made from PEG-PUTe-PEG were loaded with CDDP and indocyanine green (ICG) simultaneously...
April 17, 2017: Biomaterials
https://www.readbyqxmd.com/read/28441562/bacterial-division-ftsz-treadmills-to-build-a-beautiful-wall
#2
Kara M Schoenemann, William Margolin
The tubulin-like FtsZ protein polymerizes into a contractile ring structure required for cytokinesis in most bacteria. Two new studies report that FtsZ polymers move around the ring by treadmilling, which guides and regulates the inward growth of the septal wall.
April 24, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28441503/robust-uniform-and-highly-emissive-quantum-dot-polymer-films-and-patterns-using-thiol-ene-chemistry
#3
Markus Smith, Sidney T Malak, Jaehan Jung, Young Jun Yoon, Chun Hao Lin, Sunghan Kim, Kyung Min Lee, Ruilong Ma, Timothy J White, Timothy J Bunning, Zhiqun Lin, Vladimir V Tsukruk
This work demonstrates a facile and versatile method for generating low scattering crosslinked quantum dots (QD)-polymer composite films and patterned highly emissive structures with ultra-high QD loading, minimal phase-separation, and tunable mechanical properties. Uniform QD-polymer films are fabricated using thiol-ene chemistry, in which cross-linked polymer networks are rapidly produced in ambient conditions via fast UV polymerization in bulk to suppress QD aggregation. UV-controlled thiol-ene chemistry limits phase separation through producing highly QD loaded crosslinked composites with loading rate above majority of those reported in literature (<1%) and approaching 30%...
April 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28441033/surface-enhanced-raman-scattering-sers-active-gold-nanoparticles-decorated-on-a-porous-polymer-filter
#4
Lei Chen, Huiying Yan, Xiangxin Xue, Dayu Jiang, Yuxi Cai, Dongmei Liang, Young Mee Jung, Xiao Xia Han, Bing Zhao
In this work, we designed a process to assemble gold nanoparticles onto a three-dimensional (3D) polymer surface, which can then be monitored using surface-enhanced Raman scattering (SERS). This work is the first demonstration of the assembly of gold nanoparticles on a filter film and in situ measurement with Raman spectroscopy. Herein, a polyhexamethylene adipamide (Nylon66) film embedded in the organic filter film was used as a template to fabricate a tunable SERS-active substrate. A "hotspot"-rich gold-nanoparticle-decorated polymer substrate for SERS was prepared; this substrate exhibited high sensitivity in trace detection of targets...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28441032/observation-of-intermolecular-hydrogen-bonding-interactions-in-biosynthesized-and-biodegradable-poly-r-3-hydroxybutyrate-co-r-3-hydroxyhexanoate-in-chloroform-and-1-1-1-3-3-3-hexafluoro-2-propanol-hfip
#5
Brian J Sobieski, Isao Noda, John F Rabolt, D Bruce Chase
In this work, we describe polymer-solvent interactions in biosynthesized and biodegradable poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] (PHBHx) and the atactic homopolymer, poly(3-hydroxybutyrate) (a-PHB), which were studied both as neat polymers and in solutions of chloroform and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). Specifically, infrared frequency shifts of the carbonyl band were observed in semi-crystalline PHBHx, but not in a-PHB, because it cannot form the helical conformation required for crystallization...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28441017/equilibration-of-micelle-polyelectrolyte-complexes-mechanistic-differences-between-static-and-annealed-charge-distributions
#6
Jennifer E Laaser, Michael McGovern, Yaming Jiang, Elise Lohmann, Theresa M Reineke, David C Morse, Kevin D Dorfman, Timothy P Lodge
The role of charge density and charge annealing in polyelectrolyte complexation was investigated through systematic comparison of two micelle-polyelectrolyte systems. First, poly(dimethylaminoethyl methacrylate)-block-poly(styrene) (PDMAEMA-b-PS) micelles were complexed with poly(styrenesulfonate) (PSS) at pH values above and below the pKa of PDMAEMA to investigate the role of charge annealing in the complexation process. Second, complexes of poly(DMAEMA-stat-oligo(ethylene glycol) methyl ether methacrylate)-block-poly(styrene) (P(DMAEMA-stat-OEGMA)-b-PS) micelles with the same PSS at low pH were used to investigate how the complexation process differs when the charged sites are in fixed positions along the polymer chains...
April 25, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28441015/-bottom-up-construction-of-multi-polyprodrug-arm-hyperbranched-amphiphiles-for-cancer-therapy
#7
Pei Sun, Dong Chen, Hongping Deng, Nan Wang, Ping Huang, Xin Jin, Xinyuan Zhu
Despite of great advantages of polymer-drug conjugates (PDC) in cancer therapy, the controlling of drug loading site and degree via a facile approach remains a great challenge. Herein, combination the controllability of the "bottom-up" strategy and the stability of multi-arm hyperbranched amphiphiles, we have developed a novel multi-polyprodrug-arm hyperbranched amphiphiles (H40-star-(PHCPTMA-b-PMPC), hPCM) via reversible addition-fragmentation chain transfer (RAFT) polymerization for cancer therapy. The hPCM was constructed via two-step polymerization of an acid-labile prodrug monomer and a zwitterionic monomer, respectively...
April 25, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28441003/chemical-interaction-guided-metal-free-growth-of-large-area-hexagonal-boron-nitride-on-silicon-based-substrates
#8
Sanjay Behura, Phong Nguyen, Rousan Debbarma, Songwei Che, Michael R Seacrist, Vikas Berry
Hexagonal boron nitride (h-BN) is an ideal platform for interfacing with two-dimensional (2D) nanomaterials to reduce carrier scattering for high-quality 2D electronics. However, scalable, transfer-free growth of hexagonal boron nitride (h-BN) remains a challenge. Currently, h-BN based 2D heterostructures require exfoliation or chemical transfer of h-BN grown on metals resulting in small areas or significant interfacial impurities. Here, we demonstrate a surface-chemistry influenced transfer-free growth of large-area, uniform, and smooth h-BN directly on silicon (Si)-based substrates including Si, silicon nitride (Si3N4), and silicon dioxide (SiO2) via low-pressure chemical vapor deposition...
April 25, 2017: ACS Nano
https://www.readbyqxmd.com/read/28440940/from-the-sea-to-the-laboratory-characterization-of-microplastic-as-prerequisite-for-the-assessment-of-ecotoxicological-impact
#9
Annegret Potthoff, Kathrin Oelschlägel, Mechthild Schmitt-Jansen, Christoph Daniel Rummel, Dana Kühnel
The presence of microplastic (MP) in the aquatic environment is recognized as a global-scale pollution issue. Secondary MP particles result from an ongoing fragmentation process governed by various biotic and abiotic factors. For a reliable risk assessment of these MP particles, knowledge about interactions with biota is needed. However, extensive testing with standard organisms under reproducible laboratory conditions with well-characterized MP suspensions is not available yet. As MP in the environment represents a mixture of particles differing in properties (e...
May 2017: Integrated Environmental Assessment and Management
https://www.readbyqxmd.com/read/28440934/determining-global-distribution-of-microplastics-by-combining-citizen-science-and-in-depth-case-studies
#10
Thijs Bosker, Paul Behrens, Martina G Vijver
Microplastics (<5 mm) are contaminants of emerging global concern. They have received considerable attention in scientific research, resulting in an increased awareness of the issue among politicians and the general public. However, there has been significant variation in sampling and extraction procedures used to quantify microplastics levels. The difference in extraction procedures can especially impact study outcomes, making it difficult, and sometimes impossible, to directly compare results among studies...
May 2017: Integrated Environmental Assessment and Management
https://www.readbyqxmd.com/read/28440923/ecotoxicity-testing-of-microplastics-considering-the-heterogeneity-of-physicochemical-properties
#11
Scott Lambert, Christian Scherer, Martin Wagner
"Microplastic" is an umbrella term that covers many particle shapes, sizes, and polymer types, and as such the physical and chemical properties of environmental microplastics will differ from the primary microbeads commonly used for ecotoxicity testing. In the present article, we discuss the physical and chemical properties of microplastics that are potentially relevant to their ecotoxicity, including particle size, particle shape, crystallinity, surface chemistry, and polymer and additive composition. Overall, there is a need for a structured approach to the testing of different properties to identify which are the most relevant drivers of microplastic toxicity...
May 2017: Integrated Environmental Assessment and Management
https://www.readbyqxmd.com/read/28440837/modelling-of-thermal-transport-through-a-nanocellular-polymer-foam-toward-the-generation-of-a-new-superinsulating-material
#12
Guilong Wang, Chongda Wang, Jinchuan Zhao, Guizhen Wang, Chul B Park, Guoqun Zhao
Superinsulating materials play a pivotal role in achieving the sustainable development of our modern world by improving energy efficiency, and reducing energy consumption and CO2 emission. Nanocellular polymer foams have been considered as a promising superinsulating material, but their development is yet to be achieved. The understanding of thermal transport through the nanocellular foam is crucial for developing this superinsulating material. Herein, we report an accurate mathematical model for the first time to quantitatively estimate thermal transport through the nanocellular polymer foam...
April 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28440832/nanoemitters-and-innate-immunity-the-role-of-surfactants-and-bio-coronas-in-myeloperoxidase-catalyzed-oxidation-of-pristine-single-walled-carbon-nanotubes
#13
Cheuk Fai Chiu, Haider H Dar, Alexandr A Kapralov, Renã A S Robinson, Valerian E Kagan, Alexander Star
Single-walled carbon nanotubes (SWCNTs) are experimentally utilized in in vivo imaging and photothermal cancer therapy owing to their unique physicochemical and electronic properties. For these applications, pristine carbon nanotubes are often modified by polymer surfactant coatings to improve their biocompatibility, adding more complexity to their recognition and biodegradation by immuno-competent cells. Here, we investigate the oxidative degradation of SWCNTs catalyzed by neutrophil myeloperoxidase (MPO) using bandgap near-infrared (NIR) photoluminescence and Raman spectroscopy...
April 25, 2017: Nanoscale
https://www.readbyqxmd.com/read/28440650/comprehensive-computational-and-experimental-analysis-of-biomaterial-towards-the-behavior-of-imidazolium-based-ionic-liquids-an-interplay-between-hydrophilic-and-hydrophobic-interactions
#14
Reddicherla Umapathi, Suresh B Vepuri, Pannuru Venkatesu, Mahmoud E S Soliman
To provide insights into the aggregation behavior, hydration tendency and variation in phase transition temperature produced by the addition of ionic liquids (ILs) to poly(N-isopropylacrylamide) (PNIPAM) aqueous solution, systematic physicochemical studies, and molecular dynamic simulations were carried out. The influence of ILs possessing same [Cl]- anion and a set of cation [Cnmim]+ with increasing alkyl chain length such as 1-ethyl-3-methylimidazolium ([Emim]+), 1-allyl-3-methylimidazolium ([Amim]+), 1-butyl-3-methylimidazolium ([Bmim]+), 1-hexyl-3-methylimidazolium ([Hmim]+), 1-benzyl-3-methylimidazolium ([Bzmim]+), and 1- decyl-3-methylimidazolium ([Dmim] +) on the phase transition of PNIPAM was monitored by the aid of UV-visible absorption spectra, fluorescence intensity spectra, viscosity (ɳ), dynamic light scattering (DLS) and Fourier transform infrared (FTIR) spectroscopy...
April 25, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28440634/m-carboranylphosphinate-as-versatile-building-blocks-to-design-all-inorganic-coordination-polymers
#15
Elena Oleshkevich, Clara Viñas, Isabel Romero, Duane Choquesillo-Lazarte, Matti Haukka, Francesc Teixidor
The first examples of coordination polymers of manganese(II) and a nickel(II) complex with a purely inorganic carboranylphosphinate ligand are reported, together with its exhaustive characterization. X-ray analysis revealed 1D polymeric chains with carboranylphosphinate ligands bridging two manganese(II) centers. The reactivity of polymer 1 with water and Lewis bases has also been studied.
April 25, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28440621/gas-phase-sensing-of-alcohols-by-metal-organic-framework-polymer-composite-materials
#16
Sumit Sachdeva, Sander J H Koper, Anahid Sabetghadam, Dimitri Soccol, Dirk J Gravesteijn, Freek Kapteijn, Ernst J R Sudhölter, Jorge Gascon, Louis C P M de Smet
Affinity layers play a crucial role in chemical sensors for the selective and sensitive detection of analytes. Here, we report the use of composite affinity layers containing Metal Organic Frameworks (MOFs) in a polymeric matrix for sensing purposes. Nanoparticles of NH2-MIL-53(Al) were dispersed in a Matrimid polymer matrix with different weight ratios (0-100 wt %) and drop-casted on planar capacitive transducer devices. These coated devices were electrically analyzed using impedance spectroscopy and investigated for their sensing properties toward the detection of a series of alcohols and water in the gas phase...
April 25, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28440430/perfluorooctanoic-acid-induces-oxidative-damage-and-mitochondrial-dysfunction-in-pancreatic-%C3%AE-cells
#17
Kwang Sik Suh, Eun Mi Choi, Yu Jin Kim, Soo Min Hong, So Yong Park, Sang Youl Rhee, Seungjoon Oh, Sung Woon Kim, Youngmi Kim Pak, Wonchae Choe, Suk Chon
Several environmental contaminants have been linked to the development of diabetes and increased diabetes‑associated mortality. Perfluorooctanoic acid (PFOA) is a widely used perfluoroalkane found in surfactants and lubricants, and in processing aids used in the production of polymers. Furthermore, PFOA has been detected in humans, wildlife and the environment. The present study investigated the toxic effects of PFOA on rat pancreatic β‑cell‑derived RIN‑m5F cells. Cell viability, apoptosis, reactive oxygen and nitrogen species, cytokine release and mitochondrial parameters, including membrane potential collapse, reduced adenosine triphosphate levels, cardiolipin peroxidation and cytochrome c release were assessed...
April 11, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28440385/temporal-viscosity-modulations-driven-by-a-ph-sensitive-polymer-coupled-to-a-ph-changing-chemical-reaction
#18
D M Escala, A P Muñuzuri, A De Wit, J Carballido-Landeira
The Formaldehyde-Sulfite (FS) and the Formaldehyde-Sulfite-Gluconolactone (FSG) systems are examples of complex chemical reactions accompanied by well-controlled variations in pH. While the FS system exhibits a clock behavior, in the FSG reaction, this mechanism is coupled with the hydrolysis of the gluconolactone which gives the possibility to show large temporal oscillations of pH in an open reactor. In this work, we show how these reactive systems, due to their organic nature, can be coupled with pH sensitive polymers, particularly with polyacrylic acid (PAA) to trigger temporal changes of viscosity...
April 25, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28440372/autonomous-unimer-vesicle-oscillation-by-totally-synthetic-diblock-copolymers-effect-of-block-length-and-polymer-concentration-on-spatio-temporal-structures
#19
Ryota Tamate, Takeshi Ueki, Mitsuhiro Shibayama, Ryo Yoshida
In this study, factors controlling autonomous vesicle oscillations exhibited by self-oscillating diblock copolymers were investigated. The self-oscillating diblock copolymer contains poly(ethylene oxide) (PEO) as the hydrophilic block and a random copolymer composed of N-isopropylacrylamide (NIPAAm) with side chains of ruthenium tris(2,2'-bipyridine) (Ru(bpy)3), which catalyzes the Belousov-Zhabotinsky (BZ) reaction, as the self-oscillating block. Recently, our group has reported that a diblock copolymer exhibits a unique autonomous disintegration and reconstruction of the vesicles driven by the periodic redox changes of Ru(bpy)3 in a catalyst-free BZ reaction solution...
April 25, 2017: Soft Matter
https://www.readbyqxmd.com/read/28440371/role-of-uncrosslinked-chains-in-droplets-dynamics-on-silicone-elastomers
#20
Aurélie Hourlier-Fargette, Arnaud Antkowiak, Antoine Chateauminois, Sébastien Neukirch
We report an unexpected behavior in wetting dynamics on soft silicone substrates: the dynamics of aqueous droplets deposited on vertical plates of such elastomers exhibits two successive speed regimes. This macroscopic observation is found to be closely related to microscopic phenomena occurring at the scale of the polymer network: we show that uncrosslinked chains found in most widely used commercial silicone elastomers are responsible for this surprising behavior. A direct visualization of the uncrosslinked oligomers collected by water droplets is performed, evidencing that a capillarity-induced phase separation occurs: uncrosslinked oligomers are extracted from the silicone elastomer network by the water-glycerol mixture droplet...
April 25, 2017: Soft Matter
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