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ACS Macro Letters

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https://www.readbyqxmd.com/read/29399386/synthesis-of-degradable-poly-vinyl-alcohol-by-radical-ring-opening-copolymerization-and-ice-recrystallization-inhibition-activity
#1
Guillaume Hedir, Christopher Stubbs, Phillip Aston, Andrew P Dove, Matthew I Gibson
Poly(vinyl alcohol) (PVA) is the most active synthetic mimic of antifreeze proteins and has extremely high ice recrystallization inhibition (IRI) activity. Addition of PVA to cellular cryopreservation solutions increases the number of recovered viable cells due to its potent IRI, but it is intrinsically nondegradable in vivo. Here we report the synthesis, characterization, and IRI activity of PVA containing degradable ester linkages. Vinyl chloroacetate (VClAc) was copolymerized with 2-methylene-1,3-dioxepane (MDO) which undergoes radical ring-opening polymerization to install main-chain ester units...
December 19, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29214115/morphology-under-control-engineering-biodegradable-stomatocytes
#2
Imke A B Pijpers, Loai K E A Abdelmohsen, David S Williams, Jan C M van Hest
Biodegradable nanoarchitectures, with well-defined morphological features, are of great importance for nanomedical research; however, understanding (and thereby engineering) their formation is a substantial challenge. Herein, we uncover the supramolecular potential of PEG-PDLLA copolymers by exploring the physicochemical determinants that result in the transformation of spherical polymersomes into stomatocytes. To this end, we have engineered blended polymersomes (comprising copolymers with varying lengths of PEG), which undergo solvent-dependent reorganization inducing negative spontaneous membrane curvature...
November 21, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29226025/permeable-protein-loaded-polymersome-cascade-nanoreactors-by-polymerization-induced-self-assembly
#3
Lewis D Blackman, Spyridon Varlas, Maria C Arno, Alice Fayter, Matthew I Gibson, Rachel K O'Reilly
Enzyme loading of polymersomes requires permeability to enable them to interact with the external environment, typically requiring addition of complex functionality to enable porosity. Herein, we describe a synthetic route towards intrinsically permeable polymersomes loaded with functional proteins using initiator-free visible light-mediated polymerization-induced self-assembly (photo-PISA) under mild, aqueous conditions using a commercial monomer. Compartmentalization and retention of protein functionality was demonstrated using green fluorescent protein as a macro-molecular chromophore...
October 31, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29226024/polymers-at-liquid-vapor-interface
#4
Brandon L Peters, Darin Q Pike, Michael Rubinstein, Gary S Grest
Polymers confined to the liquid/vapor interface are studied using molecular dynamics simulations. We show that for polymers which are weakly immiscible with the solvent, the density profile perpendicular to the liquid/vapor interface is strongly asymmetric. On the vapor side of the interface, the density distribution falls off as a Gaussian with a decay length on the order of the bead diameter, whereas on the liquid side, the density profile decays as a simple exponential. This result differs from that of a polymer absorbed from a good solvent with the density profile decaying as a power law...
October 11, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29201535/polymer-informatics-opportunities-and-challenges
#5
Debra J Audus, Juan J de Pablo
We are entering an era where large volumes of scientific data, coupled with algorithmic and computational advances, can reduce both the time and cost of developing new materials. This emerging field known as materials informatics has gained acceptance for a number of classes of materials, including metals and oxides. In the particular case of polymer science, however, there are important challenges that must be addressed before one can start to deploy advanced machine learning approaches for designing new materials...
October 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29308298/core-shell-structure-and-aggregation-number-of-micelles-composed-of-amphiphilic-block-copolymers-and-amphiphilic-heterografted-polymer-brushes-determined-by-small-angle-x-ray-scattering
#6
Magdalena Szymusiak, Joseph Kalkowski, Hanying Luo, Alexander J Donovan, Pin Zhang, Chang Liu, Weifeng Shang, Thomas Irving, Margarita Herrera-Alonso, Ying Liu
A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core-shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core-shell size, and aggregation number...
September 19, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/28966880/two-dimensional-controlled-syntheses-of-polypeptide-molecular-brushes-via-n-carboxyanhydride-ring-opening-polymerization-and-ring-opening-metathesis-polymerization
#7
Jingwei Fan, Yannick P Borguet, Lu Su, Tan P Nguyen, Hai Wang, Xun He, Jiong Zou, Karen L Wooley
Well-defined molecular brushes bearing polypeptides as side chains were prepared by a "grafting through" synthetic strategy with two-dimensional control over the brush molecular architectures. By integrating N-carboxyanhydride ring-opening polymerizations (NCA ROPs) and ring-opening metathesis polymerizations (ROMPs), desirable segment lengths of polypeptide side chains and polynorbornene brush backbones were independently constructed in controlled manners. The N2 flow accelerated NCA ROP was utilized to prepare polypeptide macromonomers with different lengths initiated from a norbornene-based primary amine, and those macromonomers were then polymerized via ROMP...
September 19, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29226026/ultra-low-dispersity-poly-vinyl-alcohol-reveals-significant-dispersity-effects-on-ice-recrystallization-inhibition-activity
#8
Nicholas S Vail, Christopher Stubbs, Caroline I Biggs, Matthew I Gibson
Polymer mimics of antifreeze proteins are emerging as an exciting class of macromolecular cryoprotectants for the storage of donor cells and tissue. Poly(vinyl alcohol), PVA, is the most potent polymeric ice growth inhibitor known, but its mode of action and the impact of valency (DP) are not fully understood. Herein, tandem RAFT polymerization and column chromatography are used to isolate oligomers with dispersities <1.01 to enable the effect of molecular weight distribution, as well as length, to be probed...
August 30, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/28781926/dispersity-under-scrutiny-phase-behavior-differences-between-disperse-and-discrete-low-molecular-weight-block-co-oligomers
#9
Bas van Genabeek, Bas F M de Waal, Bianca Ligt, Anja R A Palmans, E W Meijer
An experimental study is presented in which we compare the bulk phase behavior of discrete and (partially) disperse diblock co-oligomers (BCOs) with high χ-low N. To this end, oligomers of dimethylsiloxane (oDMS) and lactic acid (oLA) were synthesized, each having either a discrete number of repeat units or a variable block length. Ligation of the blocks resulted in oDMS-oLA BCOs with dispersities ranging from <1.00001 to 1.09, as revealed by mass spectroscopy and size exclusion chromatography. The phase behavior of all BCOs was investigated by differential scanning calorimetry and small-angle X-ray scattering...
July 18, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29104818/design-and-synthesis-of-new-sulfur-containing-hyperbranched-polymer-and-theranostic-nanomaterials-for-bimodal-imaging-and-treatment-of-cancer
#10
Blaze Heckert, Tuhina Banerjee, Shoukath Sulthana, Shuguftha Naz, Riyadh Alnasser, Deaven Thompson, Guillaume Normand, Jan Grimm, J Manuel Perez, Santimukul Santra
In this study, we have synthesized a new hyperbranched polyester polymer containing sulfur-pendants (HBPE-S) in the branching points. This HBPE-S polymer is composed of spherical shaped, aliphatic three-dimensional architecture with carboxylic acid groups on the surface. The presence of sulfur pendants in the polymeric cavities demonstrated important role in the effective encapsulation of Bi-DOTA complexes ([Bi] = 5.21 μM), when compared to the previously reported polymer without sulfur pendants (HBPE, [Bi] = 1...
March 21, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/28251035/oxidation-responsive-polymers-with-a-triggered-degradation-via-arylboronate-self-immolative-motifs-on-a-polyphosphazene-backbone
#11
Aitziber Iturmendi, Uwe Monkowius, Ian Teasdale
Oxidation responsive polymers with triggered degradation pathways have been prepared via attachment of self-immolative moieties onto a hydrolytically unstable polyphosphazene backbone. After controlled main-chain growth, postpolymerization functionalization allows the preparation of hydrolytically stable poly(organo)phosphazenes decorated with a phenylboronic ester caging group. In oxidative environments, triggered cleavage of the caging group is followed by self-immolation, exposing the unstable glycine-substituted polyphosphazene which subsequently undergoes to backbone degradation to low-molecular weight molecules...
February 21, 2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29250460/biologically-triggered-delivery-of-egf-from-polymer-fiber-patches
#12
Si-Eun Kim, Parker W Lee, Jonathan K Pokorski
Wound healing is modulated by complex spatial and temporal regulation of growth factors within a wound site. Regenerative medicine seeks to generate materials that can mimic this environment for the healing of chronic or traumatic wounds. Herein, we report a programmed release of epidermal growth factor (EGF) from coextruded polymer fiber patches, which is triggered by the natural biological cascade of wound healing. Genetically engineered EGF containing a matrix metalloproteinase (MMP) cleavage site was covalently conjugated to a nonwoven poly(ε-caprolactone) (PCL) fiber mat fabricated by multilayered melt coextrusion...
2017: ACS Macro Letters
https://www.readbyqxmd.com/read/29276651/metallocene-containing-homopolymers-and-heterobimetallic-block-copolymers-via-photoinduced-raft-polymerization
#13
Peng Yang, Parasmani Pageni, Mohammad Pabel Kabir, Tianyu Zhu, Chuanbing Tang
We report the synthesis of cationic cobaltocenium and neutral ferrocene containing homopolymers mediated by photoinduced reversible addition-fragmentation chain transfer (RAFT) polymerization with a photocatalyst fac-[Ir(ppy)3]. The homopolymers were further used as macromolecular chain transfer agents to synthesize diblock copolymers via chain extension. Controlled/"living" feature of photoinduced RAFT polymerization was confirmed by kinetic studies even without prior deoxygenation. A light switch between ON and OFF provided a spatiotemporal control of polymerization...
November 15, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27933217/poly-isoprenecarboxylates-from-glucose-via-anhydromevalonolactone
#14
Nicolas R Ball-Jones, Grant W Fahnhorst, Thomas R Hoye
A short and efficient synthesis of a series of isoprenecarboxylic acid esters (ICAEs) and their corresponding polymers is presented. The base-catalyzed eliminative ring-opening of anhydromevalonolactone (3) provides isoprenecarboxylic acid (6-H), which was further transformed to the ICAEs. Reversible addition-fragmentation chain-transfer (RAFT) polymerization was used to synthesize high molecular weight (>100 kg mol(-1)) poly(isoprenecarboxylates) with dispersities (Đ) of ca. 1.5. The glass transition temperatures (Tg) and entanglement molecular weights (Me) of the poly(isoprenecarboxylates) were determined and showed similar trends to the Tg and Me values for analogous poly(acrylate esters)...
October 18, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27695648/shape-effect-of-glyco-nanoparticles-on-macrophage-cellular-uptake-and-immune-response
#15
Zhen Li, Liang Sun, Yufei Zhang, Andrew P Dove, Rachel K O'Reilly, Guosong Chen
The shells of various poly(dl-lactide)-b-poly(acrylic acid) (PDLLA-b-PAA) spherical micelles and poly(l-lactide)-b-poly(acrylic acid) (PLLA-b-PAA) cylindrical micelles were functionalized with mannose to yield glyco-nanoparticles (GNPs) with different shapes and dimensions. All of these GNPs were shown to have good biocompatibility (up to 1 mg/mL). Cellular uptake experiments using RAW 264.7 have shown that the spherical GNPs were internalized to a much greater extent than the cylindrical GNPs and such a phenomenon was attributed to their different endocytosis pathways...
September 20, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27547493/block-copolymer-membranes-for-efficient-capture-of-a-chemotherapy-drug
#16
X Chelsea Chen, Hee Jeung Oh, Jay F Yu, Jeffrey K Yang, Nikos Petzetakis, Anand S Patel, Steven W Hetts, Nitash P Balsara
We introduce the use of block copolymer membranes for an emerging application, "drug capture". The polymer is incorporated in a new class of biomedical devices, referred to as ChemoFilter, which is an image-guided temporarily deployable endovascular device designed to increase the efficacy of chemotherapy-based cancer treatment. We show that block copolymer membranes consisting of functional sulfonated polystyrene end blocks and a structural polyethylene middle block (S-SES) are capable of capturing doxorubicin, a chemotherapy drug...
August 16, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/28480130/depolymerizable-poly-o-vinyl-carbamate-alt-sulfones-as-customizable-macromolecular-scaffolds-for-mucosal-drug-delivery
#17
Kaushlendra Kumar, Eduard Jimenez Castaño, Andrew R Weidner, Adem Yildirim, Andrew P Goodwin
Interest in stimulus responsive materials and polymers has grown over the years, having shown great promise in a diverse set of applications. For drug delivery, stimulus-responsive polymers have been shown to encapsulate therapeutic cargo such as small molecule drugs or proteins, deliver them to specific locations in the body, and release them so that they can induce a therapeutic effect in the patient. Most hydrolytically degradable polymers are synthesized via nucleophilic, anionic, or cationic polymerization, which generally requires protection of nucleophilic or protic side chains prior to polymerization...
May 17, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27213117/syringyl-methacrylate-a-hardwood-lignin-based-monomer-for-high-t-g-polymeric-materials
#18
Angela L Holmberg, Kaleigh H Reno, Ngoc A Nguyen, Richard P Wool, Thomas H Epps
As viable precursors to a diverse array of macromolecules, biomass-derived compounds must impart wide-ranging and precisely controllable properties to polymers. Herein, we report the synthesis and subsequent reversible addition-fragmentation chain-transfer polymerization of a new monomer, syringyl methacrylate (SM, 2,6-dimethoxyphenyl methacrylate), that can facilitate widespread property manipulations in macromolecules. Homopolymers and heteropolymers synthesized from SM and related monomers have broadly tunable and highly controllable glass transition temperatures ranging from 114 to 205 °C and zero-shear viscosities ranging from ∼0...
May 17, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27795873/chloroquine-containing-hpma-copolymers-as-polymeric-inhibitors-of-cancer-cell-migration-mediated-by-the-cxcr4-sdf-1-chemokine-axis
#19
Fei Yu, Ying Xie, Yan Wang, Zheng-Hong Peng, Jing Li, David Oupický
Chloroquine-containing HPMA copolymers (pCQs) were synthesized for the first time by copolymerization of methacryloylated hydroxychloroquine and HPMA. The copolymers showed lower cytotoxicity when compared with hydroxychloroquine. Treatment of cancer cells with pCQ resulted in decreased surface expression of chemokine receptor CXCR4. The pCQ copolymers showed effective inhibition of CXCR4/SDF1-mediated cancer cell migration that was fully comparable with a commercial small-molecule CXCR4 antagonist AMD3100...
March 15, 2016: ACS Macro Letters
https://www.readbyqxmd.com/read/27042383/incorporating-diblock-copolymer-nanoparticles-into-calcite-crystals-do-anionic-carboxylate-groups-alone-ensure-efficient-occlusion
#20
Yin Ning, Lee A Fielding, Kay E B Doncom, Nicholas J W Penfold, Alexander N Kulak, Hideki Matsuoka, Steven P Armes
New spherical diblock copolymer nanoparticles were synthesized via RAFT aqueous dispersion polymerization of 2-hydroxypropyl methacrylate (HPMA) at 70 °C and 20% w/w solids using either poly(carboxybetaine methacrylate) or poly(proline methacrylate) as the steric stabilizer block. Both of these stabilizers contain carboxylic acid groups, but poly(proline methacrylate) is anionic above pH 9.2, whereas poly(carboxybetaine methacrylate) has zwitterionic character at this pH. When calcite crystals are grown at an initial pH of 9...
March 15, 2016: ACS Macro Letters
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