126 results match your criteria Acs Macro Letters[Journal]


Self-Assembly of Minimal Peptoid Sequences.

ACS Macro Lett 2020 Apr 19;9(4):494-499. Epub 2020 Mar 19.

Department of Pure & Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow G1 1XL, U.K.

Peptoids are biofunctional -substituted glycine peptidomimics. Their self-assembly is of fundamental interest because they demonstrate alternatives to conventional peptide structures based on backbone chirality and beta-sheet hydrogen bonding. The search for self-assembling, water-soluble "minimal" sequences, be they peptide or peptidomimic, is a further challenge. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b01010DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7179723PMC

Combinatorial Biomaterials Discovery Strategy to Identify New Macromolecular Cryoprotectants.

ACS Macro Lett 2020 Feb 7;9(2):290-294. Epub 2020 Feb 7.

Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.

Cryoprotective agents (CPAs) are typically solvents or small molecules, but there is a need for innovative CPAs to reduce toxicity and increase cell yield, for the banking and transport of cells. Here we use a photochemical high-throughput discovery platform to identify macromolecular cryoprotectants, as rational design approaches are currently limited by the lack of structure-property relationships. Using liquid handling systems, 120 unique polyampholytes were synthesized using photopolymerization with RAFT agents. Read More

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http://dx.doi.org/10.1021/acsmacrolett.0c00044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175595PMC
February 2020

Multivalent Polymer-Peptide Conjugates-A General Platform for Inhibiting Amyloid Beta Peptide Aggregation.

ACS Macro Lett 2019 Oct 30;8(10):1365-1371. Epub 2019 Sep 30.

Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801.

Protein aggregation is implicated in multiple deposition diseases including Alzheimer's Disease, which features the formation of toxic aggregates of amyloid beta (Aβ) peptides. Many inhibitors have been developed to impede or reverse Aβ aggregation. Multivalent inhibitors, however, have been largely overlooked despite the promise of high inhibition efficiency endowed by the multivalent nature of Aβ aggregates. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b00559DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7059649PMC
October 2019

Enzyme-Deoxygenated Low Parts per Million Atom Transfer Radical Polymerization in Miniemulsion and Emulsion.

ACS Macro Lett 2018 Nov 16;7(11):1317-1321. Epub 2018 Oct 16.

Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.

The development of robust oxygen-tolerant reversible deactivation radical polymerization (RDRP) systems can dramatically simplify synthesis of well-defined polymers without redundant deoxygenation procedures. Herein, we broaden the application of oxygen-tolerant RDRP from homogeneous aqueous and organic solutions to dispersed media. The glucose oxidase (GOx) degassed atom transfer radical polymerization (ATRP) was conducted in miniemulsion and emulsion systems using various catalyst regeneration methods: ARGET, ICAR, photo, and ATRP. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00711DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6897390PMC
November 2018

Cascaded Step-Growth Polymerization for Functional Polyamides with Diverse Architectures and Stimuli Responsive Characteristics.

ACS Macro Lett 2019 Mar 20;8(3):245-249. Epub 2019 Feb 20.

Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, United States.

Thiolactone ring opening and disulfide-thiol exchange were rationally coupled to develop a cascaded step-growth polymerization methodology for preparation of degradable polyamides. A variety of functionalities can be readily incorporated on to these polyamides by pre- and post-polymerization reactions. The polymers can be degraded into small molecules in the presence of biologically relevant reducing agents backbone degradation, the kinetics of which is tunable. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b00094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6822614PMC

Synthesis and 3D Printing of PEG-Poly(propylene fumarate) Diblock and Triblock Copolymer Hydrogels.

ACS Macro Lett 2018 Oct 1;7(10):1254-1260. Epub 2018 Oct 1.

Department of Polymer Science, The University of Akron, Akron, OH 44325, USA.

PEG-based hydrogels are used widely in exploratory tissue engineering applications but in general lack chemical and structural diversity. Additive manufacturing offers pathways to otherwise unattainable scaffold morphologies but has been applied sparingly to cross-linked hydrogels. Herein, mono methyl ether poly(ethylene glycol) (PEG) and PEG-diol were used to initiate the ring-opening copolymerization (ROCOP) of maleic anhydride and propylene oxide to yield well defined diblock and triblock copolymers of PEG-poly(propylene maleate) (PPM) and ultimately poly(propylene fumarate) (PPF) with different molecular mass PEG macroinitiators and block length ratios. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00720DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6812489PMC
October 2018

Enhancement of Macromolecular Ice Recrystallization Inhibition Activity by Exploiting Depletion Forces.

ACS Macro Lett 2019 Aug 9;8(8):1063-1067. Epub 2019 Aug 9.

Department of Chemistry, Warwick Medical School, and Centre for Scientific Computing, University of Warwick Coventry, CV4 7AL, United Kingdom.

Antifreeze (glyco) proteins (AF(G)Ps) are potent inhibitors of ice recrystallization and may have biotechnological applications. The most potent AF(G)Ps function at concentrations a thousand times lower than synthetic mimics such as poly(vinyl alcohol), PVA. Here, we demonstrate that PVA's ice recrystallization activity can be rescued at concentrations where it does not normally function, by the addition of noninteracting polymeric depletants, due to PVA forming colloids in the concentrated saline environment present between ice crystals. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b00386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6711362PMC

Polyoxazoline-Based Bottlebrush and Brush-Arm Star Polymers via ROMP: Syntheses and Applications as Organic Radical Contrast Agents.

ACS Macro Lett 2019 Apr 4;8(4):473-478. Epub 2019 Apr 4.

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.

The synthesis of functional poly(2-alkyl-2-oxazoline) (PAOx) copolymers with complex nanoarchitectures using a graft-through ring-opening metathesis polymerization (ROMP) approach is described. First, well-defined norbornene-terminated poly(2-ethyl-2-oxazoline) (PEtOx) macromonomers (MM) were prepared by cationic ringopening polymerization. ROMP of these MMs produced bottlebrush copolymers with PEtOx side chains. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b00016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6615754PMC

Quantitative and Mechanistic Mechanochemistry in Ferrocene Dissociation.

ACS Macro Lett 2018 Oct 14;7(10):1174-1179. Epub 2018 Sep 14.

Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States.

Ferrocene is classically regarded as being highly inert owing to the large dissociation energy of metal-cyclopentadienyl (Cp) bonds. We show that the Fe-Cp bond in ferrocene is the preferential site of mechanochemical scission in the pulsed ultrasonication of main-chain ferrocene-containing polybutadiene-derived polymers. Quantitative studies reveal that the Fe-Cp bond is similar in strength to the carbon-nitrogen bond of an azobisdialkylnitrile (bond dissociation energy < -0 kcal/mol), despite the significantly higher Fe-Cp bond dissociation energy (approximately 90 kcal/mol). Read More

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http://pubs.acs.org/doi/10.1021/acsmacrolett.8b00625
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http://dx.doi.org/10.1021/acsmacrolett.8b00625DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516481PMC
October 2018
19 Reads

Predicting Monomers for Use in Aqueous Ring-Opening Metathesis Polymerization-Induced Self-Assembly.

ACS Macro Lett 2019 Apr 3;8(4):466-472. Epub 2019 Apr 3.

School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.

Aqueous polymerization-induced self-assembly (PISA) is a well-established methodology enabling synthesis of polymeric nanoparticles of controllable morphology. Notably, PISA ring-opening metathesis polymerization (ROMPISA) is an emerging technology for block copolymer self-assembly, mainly due to its high versatility and robustness. However, a limited number of monomers suitable for core-forming blocks in aqueous ROMPISA have been reported to date. Read More

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http://dx.doi.org/10.1021/acsmacrolett.9b00117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471431PMC
April 2019
1 Read

Threading of Unconcatenated Ring Polymers at High Concentrations: Double-Folded vs Time-Equilibrated Structures.

ACS Macro Lett 2019 Feb 22;8(2):155-160. Epub 2019 Jan 22.

SISSA (Scuola Internazionale Superiore di Studi Avanzati), Via Bonomea 265, 34136 Trieste, Italy.

Unconcatenated ring polymers in concentrated solutions and melt are remarkably well described as double-folded conformations on randomly branched primitive trees. This picture though contrasts recent evidence for extensive intermingling between close-by rings in the form of long-lived topological constraints or threadings. Here, we employ the concept of ring minimal surface to quantify the extent of threadings in polymer solutions of the double-folded rings vs rings in equilibrated molecular dynamics computer simulations. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00828DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6383510PMC
February 2019
2 Reads

Glucose Single-Chain Polymer Nanoparticles for Cellular Targeting.

ACS Macro Lett 2019 Jan 18;8(1):95-101. Epub 2018 Dec 18.

Department of Biomolecular Nanotechnology, MESA+ Institute for Nanotechnology and TechMed Institute for Health and Biomedical Technologies, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands.

Naturally occurring glycoconjugates possess carbohydrate moieties that fulfill essential roles in many biological functions. Through conjugation of carbohydrates to therapeutics or imaging agents, naturally occurring glycoconjugates are mimicked and efficient targeting or increased cellular uptake of glycoconjugated macromolecules is achieved. In this work, linear and cyclic glucose moieties were functionalized with methacrylates via enzymatic synthesis and used as building blocks for intramolecular cross-linked single-chain glycopolymer nanoparticles (glyco-SCNPs). Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00812DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369679PMC
January 2019
4 Reads

Hydrolytic Degradation and Erosion of Polyester Biomaterials.

ACS Macro Lett 2018 Aug 30;7(8):976-982. Epub 2018 Jul 30.

Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843, United States.

Strategies to refine the degradation behavior of polyester biomaterials, particularly to overcome the limitations of slow hydrolytic degradation, would broaden their utility. Herein, we examine the complexities of polyester degradation behavior, its assessment and strategies for refinement. The factors governing polyester degradation are strikingly complex. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00424DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6350899PMC
August 2018
4 Reads

-Diaryl Dihydrophenazines as Photoredox Catalysts for PET-RAFT and Sequential PET-RAFT/O-ATRP.

ACS Macro Lett 2018 Jun 23;7(6):662-666. Epub 2018 May 23.

Centre for Advanced Macromolecular Design (CAMD) and Australian Centre for Nanomedicine (ACN), School of Chemical Engineering, UNSW Australia, Sydney, NSW 2052, Australia.

-Diaryl dihydrophenazines are employed as organic photoredox catalysts (PCs) for photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. The ability of these PCs to mediate PET-RAFT is heavily dependent on the ability of the PC to access a photoexcited intramolecular charge transfer state. The use of PCs displaying intramolecular charge transfer in the excited state allows for efficient PET-RAFT of a variety of monomers, including vinyl acetate, and in a wide range of solvents. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6349393PMC
June 2018
3 Reads

Enhanced Thermoelectric Power Factor of Tensile Drawn Poly(3-hexylthiophene).

ACS Macro Lett 2019 Jan 26;8(1):70-76. Epub 2018 Dec 26.

Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 41296 Göteborg, Sweden.

The thermoelectric power factor of a broad range of organic semiconductors scales with their electrical conductivity according to a widely obeyed power law, and therefore, strategies that permit this empirical trend to be surpassed are highly sought after. Here, tensile drawing of the conjugated polymer poly(3-hexylthiophene) (P3HT) is employed to create free-standing films with a high degree of uniaxial alignment. Along the direction of orientation, sequential doping with a molybdenum tris(dithiolene) complex leads to a 5-fold enhancement of the power factor beyond the predicted value, reaching up to 16 μW m K for a conductivity of about 13 S cm. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00820DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344060PMC
January 2019
3 Reads
5.242 Impact Factor

Double-Modified Glycopolymers from Thiolactones to Modulate Lectin Selectivity and Affinity.

ACS Macro Lett 2018 Dec 6;7(12):1498-1502. Epub 2018 Dec 6.

Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.

Multivalent glycomaterials show high affinity toward lectins but are often nonselective as they lack the precise 3-D presentation found in native glycans. Here, thiolactone chemistry is exploited to enable the synthesis of glycopolymers with both a primary binding (galactose) and a variable secondary binding unit in close proximity to each other on the linker. These polymers are used to target the Cholera toxin B subunit, CTxB, inspired by its native branched glycan target, GM-1. Read More

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http://pubs.acs.org/doi/10.1021/acsmacrolett.8b00825
Publisher Site
http://dx.doi.org/10.1021/acsmacrolett.8b00825DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6326524PMC
December 2018
3 Reads

Chemical Approaches to Dynamically Modulate the Properties of Synthetic Matrices.

ACS Macro Lett 2019 Jan 22;8(1):7-16. Epub 2018 Dec 22.

Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716, United States.

As knowledge about the dynamic nature of tissues within the human body has increased, the need for cell culture models that mimic the properties of these dynamic microenvironments has grown. Hydrogels are useful platforms for investigating cellular responses to microenvironment cues in disease and regeneration processes and recently have been designed to contain dynamic bonds to regulate the mechanical and biochemical properties of the matrix in three-dimensional cell culture applications. In this Viewpoint, we highlight recent advances in developing hydrogels with dynamic properties for modeling aspects of human tissues, providing control over the properties of the synthetic matrix on multiple length and time scales, and their application for understanding or directing cell response. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7220201PMC
January 2019

pH-Induced Transformation of Biodegradable Multilamellar Nanovectors for Enhanced Tumor Penetration.

ACS Macro Lett 2018 Nov 12;7(11):1394-1399. Epub 2018 Nov 12.

Bio-Organic Chemistry, Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513 (STO 3.41), 5600 MB Eindhoven, The Netherlands.

Herein we describe biodegradable nanovectors comprised of block copolymers of poly(ethylene glycol) and poly(trimethylene carbonate) (PEG-PTMC) that change their morphology and surface charge when exposed to tumor environment conditions. Well-defined, drug-loaded nanovectors were prepared via direct hydration using liquid oligo(ethylene glycol) as a dispersant. Systematic introduction of basic imidazole-functional TMC derivatives, through modular polymerization, resulted in polymers that self-assembled in multilamellar nanoparticles (at neutral pH) and that were loaded with hydrophobic drugs. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281313PMC
November 2018
3 Reads

Engineering Cell Surfaces by Covalent Grafting of Synthetic Polymers to Metabolically-Labeled Glycans.

ACS Macro Lett 2018 Nov 10;7(11):1289-1294. Epub 2018 Oct 10.

Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.

Re-engineering mammalian cell surfaces enables modulation of their phenotype, function, and interactions with external markers and may find application in cell-based therapies. Here we use metabolic glycan labeling to install azido groups onto the cell surface, which can act as anchor points to enable rapid, simple, and robust "click" functionalization by the addition of a polymer bearing orthogonally reactive functionality. Using this strategy, new cell surface functionality was introduced by using telechelic polymers with fluorescence or biotin termini, demonstrating that recruitment of biomacromolecules is possible. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00675DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6281312PMC
November 2018
4 Reads

Site-Specific Insulin-Trehalose Glycopolymer Conjugate by Grafting From Strategy Improves Bioactivity.

ACS Macro Lett 2018 Mar 20;7(3):324-329. Epub 2018 Feb 20.

Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569.

Insulin is an important therapeutic protein for the treatment of diabetes, but it is unstable and aggregates upon exposure to environmental stressors encountered during storage and transport. To prevent degradation of the protein in this manner and retain as much bioactivity as possible, a well-defined insulin-trehalose glycopolymer conjugate was synthesized. To accomplish this, a strategy was employed to site-specifically modify insulin with a polymerization initiator at a particular conjugation site; this also facilitated purification and characterization. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6241536PMC
March 2018
2 Reads

Hierarchical Self-Assembly of Supramolecular Double-Comb Triblock Terpolymers.

ACS Macro Lett 2018 Oct 13;7(10):1168-1173. Epub 2018 Sep 13.

Macromolecular Chemistry and New Polymeric Materials, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.

Involving supramolecular chemistry in self-assembling block copolymer systems enables design of macromolecular architectures that are challenging to obtain through conventional all-covalent routes. In this work we present supramolecular double-comb triblock terpolymers in which both outer blocks are able to interact with a surfactant via hydrogen bonding and thereby form a comb-shaped architecture upon complexation. While the neat triblock terpolymer only formed a triple lamellar morphology, multiple hierarchical structures were observed in these supramolecular comb-coil-comb triblock terpolymers by simply adjusting the surfactant concentration. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00570DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195812PMC
October 2018
4 Reads

Incorporation of Large Cycloalkene Rings into Alternating Copolymers Allows Control of Glass Transition and Hydrophobicity.

ACS Macro Lett 2018 Sep 16;7(9):1068-1072. Epub 2018 Aug 16.

Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States.

We previously reported that cyclohexene and bicyclo[4.2.0]oct-1(8)-ene-8-carboxamides undergo efficient ruthenium-catalyzed alternating ring-opening metathesis polymerization (AROMP). Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6156091PMC
September 2018
2 Reads

Scalable Synthesis of Multivalent Macromonomers for ROMP.

ACS Macro Lett 2018 Apr 26;7(4):472-476. Epub 2018 Mar 26.

Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.

The polymerization of functional monomers provides direct access to functional polymers without need for postpolymerization modification; however, monomer synthesis can become a bottleneck of this approach. New methods that enable rapid installation of functionality into monomers for living polymerization are valuable. Here, we report the three-step convergent synthesis (two-step longest linear sequence) of a divalent -norbornene imide capable of efficient coupling with various nucleophiles and azides to produce diversely functionalized branched macromonomers optimized for ring-opening metathesis polymerization (ROMP). Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162068PMC
April 2018
6 Reads
5.240 Impact Factor

Self-Assembly of Electrostatic Cocrystals from Supercharged Fusion Peptides and Protein Cages.

ACS Macro Lett 2018 Mar 19;7(3):318-323. Epub 2018 Feb 19.

Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, FI-00076 Aalto, Finland.

Self-assembly is a convenient process to arrange complex biomolecules into large hierarchically ordered structures. Electrostatic attraction between the building blocks is a particularly interesting driving force for the assembly process, as it is easily tunable and reversible. Large biomolecules with high surface charge density, such as proteins and protein cages, are very promising building blocks due to their uniform size and shape. Read More

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https://pubs.acs.org/doi/10.1021/acsmacrolett.8b00023
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http://dx.doi.org/10.1021/acsmacrolett.8b00023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6156108PMC
March 2018
4 Reads

Self-Coacervation of a Silk-Like Protein and Its Use As an Adhesive for Cellulosic Materials.

ACS Macro Lett 2018 Sep 5;7(9):1120-1125. Epub 2018 Sep 5.

Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-02150, Espoo, Finland.

Liquid-liquid phase separation of biomacromolecules plays a critical role in many of their functions, both as cellular components and in structural assembly. Phase separation is also a key mechanism in the assembly of engineered recombinant proteins for the general aim to build new materials with unique structures and properties. Here the phase separation process of an engineered protein with a block-architecture was studied. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00527DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150716PMC
September 2018
4 Reads

Organocatalyzed Atom Transfer Radical Polymerization Catalyzed by Core Modified -Aryl Phenoxazines Performed under Air.

ACS Macro Lett 2018 Aug 6;7(8):1016-1021. Epub 2018 Aug 6.

Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States of America.

Organocatalyzed atom transfer radical polymerization (O-ATRP) was performed under air using core modified -aryl phenoxazines as photoredox catalysts (PCs) to synthesize poly(methyl methacrylate) in a controlled fashion with initiator efficiency (* = / × 100) ranging from 84 to 99% and dispersity being ∼1.2-1.3. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00497DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6905434PMC

Nanoconfinement-Induced β-Phase Formation Inside Poly(vinylidene fluoride)-Based Block Copolymers.

ACS Macro Lett 2018 Jul 2;7(7):863-867. Epub 2018 Jul 2.

Macromolecular Chemistry and New Polymeric Materials, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.

The electroactive properties of poly(vinylidene fluoride) (PVDF) are a direct consequence of its crystalline phases. Although poorly understood, nanostructuring PVDF in confined geometries can drastically change its crystallization behavior. Therefore, we synthesized a variety of PVDF-based triblock copolymers to gain a better understanding of the melt crystallization and explore how crystallization is affected by the morphology and chemical nature of the amorphous block. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00418DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6052937PMC
July 2018
2 Reads

Direct ATRP of Methacrylic Acid with Iron-Porphyrin Based Catalysts.

ACS Macro Lett 2018 Jan 14;7(1):26-30. Epub 2017 Dec 14.

Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.

An iron porphyrin catalyst, derived from the active center of proteins such as horseradish peroxidase and hemoglobin, was successfully used for the atom transfer radical polymerizations (ATRP) of methacrylic acid. ATRP of methacrylic acid and other acidic monomers is challenging due to Cu complexation by carboxylates, protonation of the ligand, and displacement of the halogen chain end. A robust mesohemin-based catalyst provided controlled ATRP of methacrylic acid, yielding poly(methacrylic acid) with ≥ 20000 and dispersity < 1. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00909DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6023406PMC
January 2018
11 Reads

Consequences of Dispersity on the Self-Assembly of ABA-Type Amphiphilic Block Co-Oligomers.

ACS Macro Lett 2018 May 16;7(5):546-550. Epub 2018 Apr 16.

Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Intriguingly, little is known about the impact of dispersity on the crystallization driven self-assembly (CDSA) of amphiphilic block copolymers in aqueous media. Here, we investigate the influence of dispersity on the CDSA of ABA-type amphiphilic block co-oligomers (ABCOs). Two pairs of ABCOs are synthesized comprising discrete ( = 1. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00168DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5973780PMC
May 2018
3 Reads

Triggerable Multivalent Glyconanoparticles for Probing Carbohydrate-Carbohydrate Interactions.

ACS Macro Lett 2018 Feb 18;7(2):178-183. Epub 2018 Jan 18.

Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, U.K.

Carbohydrate-carbohydrate interactions are proposed to be biologically significant but have lower affinities than the well-studied carbohydrate-protein interactions. Here we introduce multivalent glyconanostructures where the surface expression of lactose can be triggered by an external stimulus, and a gold nanoparticle core enables colorimetric signal outputs to probe binding. Macromolecular engineering of a responsive polymer "gate" enables the lactose moieties to be presented only when an external stimulus is present, mimicking how nature uses enzymes to dynamically regulate glycan expression. Read More

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http://pubs.acs.org/doi/10.1021/acsmacrolett.7b00891
Publisher Site
http://dx.doi.org/10.1021/acsmacrolett.7b00891DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5894439PMC
February 2018
7 Reads

Thermal Isomerization of Hydroxyazobenzenes as a Platform for Vapor Sensing.

ACS Macro Lett 2018 Mar 10;7(3):381-386. Epub 2018 Mar 10.

Laboratory of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101, Tampere, Finland.

Photoisomerization of azobenzene derivatives is a versatile tool for devising light-responsive materials for a broad range of applications in photonics, robotics, microfabrication, and biomaterials science. Some applications rely on fast isomerization kinetics, while for others, bistable azobenzenes are preferred. However, solid-state materials where the isomerization kinetics depends on the environmental conditions have been largely overlooked. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5871339PMC
March 2018
6 Reads

Primitive Path Analysis and Stress Distribution in Highly Strained Macromolecules.

ACS Macro Lett 2018 Jan 29;7(1):107-111. Epub 2017 Dec 29.

Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128, Mainz, Germany.

Polymer material properties are strongly affected by entanglement effects. For long polymer chains and composite materials, they are expected to be at the origin of many technically important phenomena, such as shear thinning or the Mullins effect, which microscopically can be related to topological constraints between chains. Starting from fully equilibrated highly entangled polymer melts, we investigate the effect of isochoric elongation on the entanglement structure and force distribution of such systems. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828704PMC
January 2018
3 Reads

Synthesis of Degradable Poly(vinyl alcohol) by Radical Ring-Opening Copolymerization and Ice Recrystallization Inhibition Activity.

ACS Macro Lett 2017 Dec 1;6(12):1404-1408. Epub 2017 Dec 1.

Department of Chemistry, University of Warwick, Coventry CV4 7AL, U.K.

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 . Here we report the synthesis, characterization, and IRI activity of PVA containing degradable ester linkages. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00905DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5792090PMC
December 2017
5 Reads

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.

ACS Macro Lett 2017 Sep 31;6(9):1005-1012. Epub 2017 Aug 31.

Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60607, United States.

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)--poly(caprolactone) (PEG--PCL), poly(ethylene oxide)--poly(lactic acid) (PEG--PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA--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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5749421PMC
September 2017
14 Reads

Synthesis of Polymer Bioconjugates via Photoinduced Atom Transfer Radical Polymerization under Blue Light Irradiation.

ACS Macro Lett 2018 27;7(10):1248-1253. Epub 2018 Sep 27.

Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States.

A rapid blue-light-induced atom transfer radical polymerization (ATRP) was conducted in a biologically friendly environment. Well-controlled polymerization of oligo(ethylene oxide) methyl ether methacrylate (OEOMA) was successfully performed in aqueous media (1X PBS) under irradiation by blue LED strips. With 10. Read More

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http://dx.doi.org/10.1021/acsmacrolett.8b00609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6901285PMC
September 2018

Metallocene-Containing Homopolymers and Heterobimetallic Block Copolymers via Photoinduced RAFT Polymerization.

ACS Macro Lett 2016 Nov 4;5(11):1293-1300. Epub 2016 Nov 4.

Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, South Carolina 29208, United States.

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)]. 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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.6b00743DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5739086PMC
November 2016
9 Reads

Biologically Triggered Delivery of EGF from Polymer Fiber Patches.

ACS Macro Lett 2017 18;6(6):593-597. Epub 2017 May 18.

Department of Macromolecular Science and Engineering, Case Western Reserve University, Case School of Engineering, Cleveland, Ohio 44106, United States.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00212DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5726586PMC
May 2017
4 Reads

Ultra-Low Dispersity Poly(vinyl alcohol) Reveals Significant Dispersity Effects on Ice Recrystallization Inhibition Activity.

ACS Macro Lett 2017 Aug;6(9):1001-1004

Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718289PMC
August 2017
5 Reads

Permeable Protein-Loaded Polymersome Cascade Nanoreactors by Polymerization-Induced Self-Assembly.

ACS Macro Lett 2017 Oct;6(11):1263-1267

Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00725DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718297PMC
October 2017
101 Reads

Polymers at Liquid/Vapor Interface.

ACS Macro Lett 2017 Oct;6(11):1191-1195

Sandia National Laboratories, Albuquerque, New Mexico 87185, United States.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00466DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5718204PMC
October 2017
9 Reads

Morphology Under Control: Engineering Biodegradable Stomatocytes.

ACS Macro Lett 2017 Nov 19;6(11):1217-1222. Epub 2017 Oct 19.

Eindhoven University of Technology, P.O. Box 513 (STO 3.31), 5600MB Eindhoven, The Netherlands.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00723DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5708263PMC
November 2017
12 Reads

Polymer Informatics: Opportunities and Challenges.

ACS Macro Lett 2017 Oct 15;6(10):1078-1082. Epub 2017 Sep 15.

The Institute for Molecular Engineering, The University of Chicago, Chicago, Illinois, 60637 USA.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00228DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5702941PMC
October 2017
6 Reads

Design and Synthesis of New Sulfur-Containing Hyperbranched Polymer and Theranostic Nanomaterials for Bimodal Imaging and Treatment of Cancer.

ACS Macro Lett 2017 Mar 20;6(3):235-240. Epub 2017 Feb 20.

Department of Chemistry, Pittsburg State University, 1701 S. Broadway Street, Pittsburg, KS 66762, USA.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5667566PMC
March 2017
6 Reads

Two-Dimensional Controlled Syntheses of Polypeptide Molecular Brushes via -Carboxyanhydride Ring-Opening Polymerization and Ring-Opening Metathesis Polymerization.

ACS Macro Lett 2017 Sep 8;6(9):1031-1035. Epub 2017 Sep 8.

Departments of Chemistry, Chemical Engineering, Materials Science and Engineering, and Laboratory for Synthetic-Biologic Interactions, Texas A&M University, P.O. Box 30012, 3255 TAMU, College Station, Texas 77842, United States.

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 -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 N 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. Read More

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http://pubs.acs.org/doi/10.1021/acsmacrolett.7b00603
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http://dx.doi.org/10.1021/acsmacrolett.7b00603DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5617330PMC
September 2017
11 Reads

Dispersity under Scrutiny: Phase Behavior Differences between Disperse and Discrete Low Molecular Weight Block Co-Oligomers.

ACS Macro Lett 2017 Jul 14;6(7):674-678. Epub 2017 Jun 14.

Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

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 . To this end, oligomers of dimethylsiloxane (DMS) and lactic acid (LA) were synthesized, each having either a discrete number of repeat units or a variable block length. Ligation of the blocks resulted in DMS-LA BCOs with dispersities ranging from <1. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00266DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526650PMC
July 2017
4 Reads

Depolymerizable Poly(O-vinyl carbamate--sulfones) as Customizable Macromolecular Scaffolds for Mucosal Drug Delivery.

ACS Macro Lett 2016 May 4;5(5):636-640. Epub 2016 May 4.

Department of Chemical and Biological Engineering. University of Colorado Boulder. Boulder, CO 80303, USA.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.6b00219DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5417698PMC
May 2016
42 Reads

Oxidation Responsive Polymers with a Triggered Degradation via Arylboronate Self-Immolative Motifs on a Polyphosphazene Backbone.

ACS Macro Lett 2017 Feb 2;6(2):150-154. Epub 2017 Feb 2.

Institute of Polymer Chemistry and Institute of Inorganic Chemistry, Johannes Kepler University Linz , Altenberger Straße 69, 4040 Linz, Austria.

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. Read More

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http://dx.doi.org/10.1021/acsmacrolett.7b00015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5322476PMC
February 2017
16 Reads

Visible-Light-Initiated Thiol-Michael Addition Polymerizations with Coumarin-Based Photobase Generators: Another Photoclick Reaction Strategy.

ACS Macro Lett 2016 Feb 22;5(2):229-233. Epub 2016 Jan 22.

Department of Chemical and Biological Engineering, University of Colorado, UCB 596, Boulder, Colorado 80309, United States.

An efficient visible-light-sensitive photobase generator for thiol-Michael addition reactions was synthesized and evaluated. This highly reactive catalyst was designed by protecting a strong base (tetramethyl guanidine, TMG) with a visible-light-responsive group which was a coumarin derivative. The coumarin-coupled TMG was shown to exhibit extraordinary catalytic activity toward initiation of the thiol-Michael reaction, including thiol-Michael addition-based polymerization, upon visible-light irradiation, leading to a stoichiometric reaction of both thiol and vinyl functional groups. Read More

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http://dx.doi.org/10.1021/acsmacrolett.5b00923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5176105PMC
February 2016
5 Reads

Poly(isoprenecarboxylates) from Glucose via Anhydromevalonolactone.

ACS Macro Lett 2016 Oct 20;5(10):1128-1131. Epub 2016 Sep 20.

Department of Chemistry, 207 Pleasant St., SE, University of Minnesota, Minneapolis, MN 55455.

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 () provides isoprenecarboxylic acid (), which was further transformed to the ICAEs. Reversible addition-fragmentation chain-transfer (RAFT) polymerization was used to synthesize high molecular weight (>100 kg mol) poly(isoprenecarboxylates) with dispersities () of ca. Read More

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http://dx.doi.org/10.1021/acsmacrolett.6b00560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5137944PMC
October 2016
6 Reads

Rate-Dependent Stiffness and Recovery in Interpenetrating Network Hydrogels through Sacrificial Metal Coordination Bonds.

ACS Macro Lett 2015 Nov 15;4(11):1200-1204. Epub 2015 Oct 15.

Graduate Program in Biomolecular Science and Engineering, University of California, Santa Barbara, California 93106, United States; Marine Science Institute, University of California, Santa Barbara, California 93106, United States.

Four-arm poly(ethylene glycol) (PEG) star polymers modified with 3-hydroxy-4-pyridinone (HOPO) end groups were shown to form transient, coordination networks upon addition of trivalent cations In, Fe, and Al. These coordination-based hydrogels exhibited high activation energies of viscoelasticity (34 kT) and characteristic bond lifetimes tunable over 2 orders of magnitude and could be incorporated into poly(hydroxyethylacrylamide)-based covalent scaffolds to create interpenetrating network hydrogels. Measurements carried out in compression and tension demonstrate that the secondary coordination network imparts toughness and stiffness to the overall material, and unlike traditional interpenetrating networks (IPNs), the extent of toughening is dependent on the rate at which the materials are deformed. Read More

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http://dx.doi.org/10.1021/acsmacrolett.5b00664DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5096649PMC
November 2015
9 Reads