Polymer Chemistry Blog

The synthesis of highly hemo- and cytocompatible zwitterionic 2-oxazoline-based poly(sulfobetaine)s and poly(carboxybetaine)s, which demonstrate beneficial anticoagulant activity, has been reported by Schubert et al.

The polymers were obtained by thiol–ene photoaddition of a tertiary amine-containing thiol onto an alkene-containing precursor copoly(2-oxazoline), followed by betainization with 1,3-propansultone and β-propiolactone. The polymers and their intermediates were characterized by means of 1H NMR spectroscopy and size exclusion chromatography. The influence of the zwitterionic polymers on the aggregation and hemolysis of erythrocytes, the whole blood viscosity, the platelet and complement activation as well as the blood coagulation has been studied in detail. In addition, the cytotoxicity of the materials has been evaluated.

It was found that the zwitterionic POx show no negative interactions with blood. Moreover, anticoagulant activity via the intrinsic and/or the common coagulation pathway was observed. The high hemocompatibility and the low cytotoxicity as well as the beneficial anticoagulant activity of the presented zwitterionic poly(2-oxazoline)s demonstrate their potential for the use in biomedical applications.

Zwitterionic poly(2-oxazoline)s as promising candidates for blood contacting applications by Lutz Tauhardt, David Pretzel, Kristian Kempe, Michael Gottschaldt, Dirk Pohlers and  Ulrich S. Schubert Polym. Chem. 2014, 5, 5751-5764.

Remzi Becer is a web-writer and advisory board member for Polymer Chemistry. He is currently a Senior Lecturer in Materials Science and the director of the Polymer Science and Nanotechnology masters programme at Queen Mary, University of London. Visit www.becergroup.com for more information!

Exploiting the coumarin dimerization mechanism upon UV irradiation at 365 nm, Foster and co-workers developed mechanically adaptive nanocomposites in which light can be used to change the materials properties. CNCs derived from tunicates were functionalized with 7-coumaryl-(6-isocyanatohexyl) carbamate to afford coumarin-derivatized CNCs (Cou-CNCs). Light-responsive nanocomposites were prepared by reinforcing a rubbery ethylene oxide–epichlorohydrin copolymer (EO–EPI) matrix with Cou-CNCs. The as-prepared nanocomposites show a significantly increased tensile storage modulus (E′) in comparison to the neat EO–EPI. The optically induced reaction between Cou-CNCs also reduced the swelling of the EO–EPI/Cou-CNC nanocomposites upon exposure to water as well as the extent of water-induced softening.

Photoswitchable nanocomposites made from coumarin-functionalized cellulose nanocrystals by Mahesh V. Biyani, Christoph Weder and E. Johan Foster Polym. Chem. 2014, 5, 5501-5508.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Ling, Hogen-Esch and co-workers reported a styrene-type macromonomer containing polyfluorene pendent group (PFS), which allowed the convenient synthesis of well-defined copolymers of PFS with t-butyl acrylate by both RAFT and ATRP polymerization methods. After hydrolysis, the amphiphilic copolymers self-assembled into photoluminescent nanoparticles in aqueous solution. When doped with selected dyes, the nanoparticles emitted light with tunable colors as well as white via Förster energy transfer from the excited pendent polyfluorene groups.

White light emission of multi-chromophore photoluminescent nanoparticles using polyacrylate scaffold copolymers with pendent polyfluorene groups by Chao Deng, Peng Jiang, Xiaobin Shen, Jun Ling and Thieo E. Hogen-Esch, Polym. Chem. 2014, 5, 5109-5115.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Xing and co-workers developed a new penetration enhancer based on hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine (HP-β-CD–PEI). Its penetration mechanism relied on a change of the secondary structure of keratin in the stratum corneum to enhance the transcutaneous permeation of drugs. By using a series of in vitro and in vivo methods, this cationic polymer demonstrated great biocompatibility and could be valuable for topical delivery as a penetration enhancer to improve the penetration of hydrophilic drugs.

In vitro and in vivo application of hydroxypropyl-β-cyclodextrin-grafted polyethyleneimine used as a transdermal penetration enhancer by Ke Wang, Yan Yan, Guilan Zhao, Wei Xu, Kai Dong, Cuiyu You, Lu Zhang and Jianfeng Xing, Polym. Chem. 2014, 5, 4658-4669.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Rozes and co-workers prepared new dynamic materials, that can repair themselves after strong damage, by hybridization of polymers with structurally well-defined nanobuilding units. The controlled design of cross-linked poly(n-butyl acrylate) (PnBA) has been performed by introducing a very low amount of a specific tin oxo-cluster. Sacrificial domains with non-covalent interactions (i.e. ionic bonds) developed at the hybrid interface play a double role. Such interactions are strong enough to cross-link the polymer, which consequently exhibits rubber-like elasticity behavior, and labile enough to enable, after severe mechanical damage, dynamic bond recombination leading to an efficient healing process at room temperature. In agreement with the nature of the reversible links at the hybrid interface, the healing process can speed up considerably with temperature .

Nano-building block based-hybrid organic–inorganic copolymers with self-healing properties by F. Potier, A. Guinault, S. Delalande, C. Sanchez, F. Ribot and L. Rozes, Polym. Chem. 2014, 5, 4474-4479.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Hoogenboom and co-workers report the optimization of the Cu(0)-mediated polymerization of n-butyl acrylate (BA) and 2-methoxyethyl acrylate (MEA) via Cu(0)-mediated polymerization using an automated parallel synthesizer.  Using this robot, up to 16 kinetic reactions could be performed in parallel, resulting in a fast screening of different reaction conditions. Several parameters were optimized to determine the optimal reaction conditions with regard to control over the polymerization and reaction rate. These optimal reaction conditions were then used for the one-pot two-step synthesis of diblock copolymers by sequential monomer addition. Altogether, this work shows the power of high-throughput optimization of Cu(0)-mediated polymerization reaction conditions. As such, it may serve to accelerate optimization of Cu(0)-mediated polymerization conditions and aid in gaining fundamental understanding of the effects of various parameters on the Cu(0)-mediated polymerization.

Cu(0)-mediated polymerization of hydrophobic acrylates using high-throughput experimentation by Lenny Voorhaar, Sofie Wallyn, Filip E. Du Prez and Richard Hoogenboom, Polym. Chem. 2014, 5, 4268-4276.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Zhu and co-workers prepared fully biodegradable antimicrobial hydrogels via a thiol–ene “click” reaction under human physiological conditions using multifunctional poly(ethylene glycol) (PEG) derivatives as precursors. Water soluble and degradable PEG derivatives with multi-enes and multi-thiols, respectively, were synthesized by polycondensation of oligo(ethylene glycol) (OEG) with “clickable” monomers. Ammonium groups with long alkyl chains were incorporated into one of the precursors covalently, using dodecyl bis(2-hydroxyethyl) methylammonium chloride as a comonomer.  These types of cationic PEG-type hydrogels showed strong antibacterial abilities against both Gram- negative and Gram-positive bacteria due to the ammonium moieties. Moreover, the hydrogel with fewer ammonium moieties still possessed significant antibacterial abilities, but low toxicity, and has the potential to be used as a medical material.

Fully biodegradable antibacterial hydrogels via thiol–ene “click” chemistry by Hong Du, Guangyu Zha, Lilong Gao, Huan Wang, Xiaodong Li, Zhiquan Shena and Weipu Zhu, Polym. Chem. 2014, 5, 4002-4008.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this work, Deng, Wang and co-workers prepared Artemisia argyi oil (AAO)-loaded macroporous antibacterial hydrogels by polymerization of oil-in-water Pickering HIPEs. The HIPEs were stabilized by the synergy of hydrophilic silica nanoparticles (N20) and surfactant Tween 80. The void interconnectivity and pore size of the hydrogels can be readily tailored by varying the concentrations of N20 nanoparticles and Tween 80. The in vitro release of the AAO-loaded hydrogels with different inner morphologies was evaluated and showed controlled release activity. The antibacterial activity of the AAO-loaded hydrogel was evaluated against Staphylococcus aureus and Escherichia coli. This kind of hydrogel exhibited excellent and long-term antibacterial activity indicating its potential use in biomedical and infection prevention applications.

Macroporous antibacterial hydrogels with tunable pore structures fabricated by using Pickering high internal phase emulsions as templates by Shengwen Zou, Zengjiang Wei, Yang Hu, Yonghong Deng, Zhen Tonga and Chaoyang Wang, Polym. Chem. 2014, 5, 4227-4234.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this article, Endo, Timur, Yagci and co-workers reported on a simple and efficient approach for the electrochemical deposition of polypeptides as bio-based covering materials for surface design. The method involves N-carboxyanhydride (NCA) ring-opening polymerization from its precursor to form a thiophene-functionalized polypeptide macromonomer (T-Pala), followed by electropolymerization. The obtained conducting polymer, namely polythiophene-g-polyalanine (PT-Pala), was characterized and utilized as a matrix for biomolecule attachment. The biosensing applicability of PT-Pala was also investigated by using glucose oxidase (GOx) as a model enzyme to detect glucose. Finally, the antimicrobial activities of newly synthesized T-Pala and PT-Pala were also evaluated. Interestingly, this technique is experimentally facile and can be applied to various types of polypeptides.

Electrochemical deposition of polypeptides: bio-based covering materials for surface design by Huseyin Akbulut, Murat Yavuz, Emine Guler, Dilek Odaci Demirkol, Takeshi Endo, Shuhei Yamada, Suna Timur and Yusuf Yagci, Polym. Chem. 2014, 5, 3929-3936.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.

In this article, Albertsson and co-workers felt inspired to use γ-lactones as inexpensive and straightforward monomers that can bestow the desired functionality on commonly used aliphatic polyester. More specifically, they used α-bromo-γ-butyrolactone (αBrγBL) as a comonomer with ε-caprolactone (εCL) or L-lactide (LLA) to produce copolymers with active and available grafting sites, e.g., for SET-LRP, where the choice of the grafting monomers is limited only by one’s imagination. The authors believe that αBrγBL inherently holds all the prerequisites to act as a platform monomer for the synthesis of functional aliphatic polyesters, i.e., it is inexpensive, available, and able to form isolated grafting sites along the polymer chain. The incorporation of isolated αBrγBL is a feature that makes this class of copolymers unique and is considered to provide a route to the “perfect graft copolymer” with a degradable backbone.

Establishing α-bromo-γ-butyrolactone as a platform for synthesis of functional aliphatic polyesters – bridging the gap between ROP and SET-LRP by Peter Olsén, Jenny Undin, Karin Odeliusa and Ann-Christine Albertsson, Polym. Chem. 2014, 5, 3847-3854.

Julien Nicolas is a web-writer and advisory board member for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.