Polymer Chemistry Blog

In this article, Stenzel and co-workers designed three different macromolecular Pt-drugs using Cu-click chemistry to attach a bidentate amino ligand to the polymer. Two statistical copolymers with different ligand densities were prepared, which were compared to the block copolymer. DNA binding studies revealed that the statistical copolymer with the highest density of Pt-drugs had the highest affinity to the DNA, due to a multivalent effect. Interestingly, when evaluating the cytotoxic effect of these macromolecular drugs using OVCAR-3 cells the activities of all three polymer architectures were similar. It can therefore be concluded that although DNA binding tests may give an initial indication on the ability of the structure to bind to the DNA, they cannot predict the outcome.

Macromolecular platinum-drugs based on statistical and block copolymer structures and their DNA binding ability by Khairil Juhanni Abd Karim, Sandra Binauld, Wei Scarano and Martina H. Stenzel Polym. Chem. 2013, 4, 5542-5554.

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

In this context, Tao, Wei and co-workers have revisited the Biginelli reaction as a potential tri-component click chemistry. Through the quick and efficient modification of polymer side groups and locking of two polymer chains, Biginelli-type homopolymers and Biginelli-locked copolymers can be facilely and quantitatively obtained. Moreover, the Biginelli reaction showed good compatibility with RAFT polymerization to construct a one-pot MCP system. Both reactions proceeded well without interference, and almost neat Biginelli functionalized homopolymers were successfully achieved in a one-pot fashion. More importantly, the Biginelli reaction can also be recognized as a ‘catalyst-free’ bioorthogonal-click reaction, through which a fluorescent probe can be covalently anchored onto cell membranes without external addition of a catalyst, implying the potential application of the Biginelli reaction in chemical biology.

A new insight into the Biginelli reaction: the dawn of multicomponent click chemistry? by Chongyu Zhu, Bin Yang, Yuan Zhao, Changkui Fu, Lei Tao and Yen Wei Polym. Chem. 2013, 4, 5395-5400.

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

In their paper, Leclerc and co-workers reported the preparation of N-octylthieno[3,4-c]pyrrole-4,6-dione with 4,4-bis(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]silole (PDTSiTPD) and 4,4-bis(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]germole (PDTGeTPD), which have exhibited high efficiencies in organic solar cells, using direct (hetero)arylation polymerization methodologies. In order to circumvent side reactions leading to cross-linked polymers, a number of new dithieno[3,2-b:2′,3′-d]silole (DTSi) monomers were prepared where the β-positions were blocked with alkyl chains and the alkyl groups on the heteroatom were modified. Co-polymers were synthesized with N-alkylthieno[3,4-c]pyrrole-4,6-dione (TPD) and the oxygen congener, N-alkylfuro[3,4-c]pyrrole-4,6-dione (FPD).

Direct heteroarylation of β-protected dithienosilole and dithienogermole monomers with thieno[3,4-c]pyrrole-4,6-dione and furo[3,4-c]pyrrole-4,6-dione by Lauren G. Mercier, Badrou Réda Aïch, Ahmed Najari, Serge Beaupré, Philippe Berrouard, Agnieszka Pron, Amélie Robitaille, Ye Tao and Mario Leclerc Polym. Chem. 2013, 4, 5252-5260.

This article is part of the Polymer Chemistry themed collection on Conjugated polymers.

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

In their study, Iyer and co-workers synthesized a non toxic conjugated polymer, poly(1,4-bis-(8-(8-hydroxyquinoline)-octyloxy)-benzene) (PHQ), able to bind iron containing heme and non-heme proteins, such as ferritin, at nanomolar levels with the highest known selectivity in cerebrospinal fluid (CSF). It has been employed to interact with the bound iron, including non-heme ferritin, in the Ab protofibril aggregates and to diminish their accumulation. The anti-AD activity of PHQ was confirmed via in vitro control studies by doping CSF of healthy individuals with Ab(1–40) with and without iron using a Thioflavin-T binding assay test and electron microscopy analysis. This new strategy to clear the cerebral deposits using conjugated polymers enables the toxic aggregated Ab peptide fibrils present in the CSF to be successfully disrupted under physiological conditions.

A rapid and sensitive detection of ferritin at a nanomolar level and disruption of amyloid β fibrils using fluorescent conjugated polymer by B. Muthuraj, Sameer Hussain and Parameswar Krishnan Iyer, Polym. Chem. 2013, 4, 5096-5107 .

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

In the present study, Connal and co-workers established a versatile strategy to prepare a diverse range of self-assembled colloidal nanostructures from the same hydrophobic BCP.  Polymer nanoparticles with well-ordered phase separated morphology were accessed from the solution self-assembly of a hydrophobic polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) BCP. However, the introduction of a hydrophilic guest capable of hydrogen bonding with the pyridine block resulted in an amphiphilic BCP, thus drastically altering the self-assembly behavior and leading to traditional spherical micelles in water. Furthermore, a hydrophobic guest was incorporated into the BCP which formed internally nanostructured assemblies in water with the hydrophobic guest entrapped within the nanoparticle. Their methodology can be used to engineer new systems that incorporate and release guests upon triggered disruption of the supramolecular bonds. Furthermore, the diversity of nanostructures that can be tuned by the incorporation of different guests enables opportunities for outstanding control of the nanoparticle properties.

Supramolecular guests in solvent driven block copolymer assembly: from internally structured nanoparticles to micelles by Daniel Klinger, Maxwell J. Robb, Jason M. Spruell, Nathaniel A. Lynd, Craig J. Hawker and Luke A. Connal, Polym. Chem. 2013, 4, 5038-5042.

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

Inspired by the success of polymer-composite materials in replacing metals across a range of high value products, Hayes and co-workers have investigated the possibility of producing nanoparticle-reinforced, supramolecular, healable composites. The material comprises a blend of three components: a pyrene-functionalized polyamide, a polydiimide and pyrene-functionalized gold nanoparticles (P-AuNPs). The polymeric components interact by forming well-defined π–π stacked complexes between π-electron rich pyrenyl residues and π-electron deficient polydiimide residues. Complexation studies in solution demonstrate that the introduction of P-AuNPs results in more rapid formation of an insoluble supramolecular network when compared to control samples that did not contain the P-AuNPs. Films of the nanocomposite are tough and flexible, and contain a relatively homogeneous dispersion of P-AuNPs. Films containing P-AuNPs are stronger and stiffer than those cast from the same polymers but without P-AuNPs, and also than films containing AuNPs that lacked the pyrenyl motif. Healing studies using a classic break/heal test, followed by stress–strain analysis, showed that materials containing up to 10 wt% P-AuNPs can even exhibit healing efficiencies of more than 100%.

Molecular recognition between functionalized gold nanoparticles and healable, supramolecular polymer blends – a route to property enhancement by Rajendran Vaiyapuri, Barnaby W. Greenland, Howard M. Colquhoun, Joanne M. Elliott and Wayne Hayes, Polym. Chem. 2013, 4, 4902-4909.

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

In this context, by combining atom-transfer radical polymerization (ATRP) with thiol–epoxy‘click’ chemistry, Khan and co-workers described a general and effient synthetic scheme, free from the usual protection/deprotection requirement of organic synthesis, for installation of two different types of functional groups at a polymer chainend. This strategy also allowed for total control over the number of the chain-end functionalities. In essence, the present strategy established a novel, modular and efficient route to chain-end multifunctional polymers with chemically complex yet molecularly precise structures and is expected to impact the current design of functional soft materials targeted for sophisticated applications.

Protecting-group-free synthesis of chain-end multifunctional polymers by combining ATRP with thiol–epoxy ‘click’ chemistry by Ikhlas Gadwal and Anzar Khan, Polym. Chem., 2013, 4, 2440-2444.

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

In this communication, Yuan and co-workers prepared mesoporous polyelectrolyte networks through the ionic complexation between imidazolium-based cationic PILs and organic oligoacids in ammonia-containing diethyl ether. The as-synthesized porous networks exhibited good structural stability and large specific surface area up to 290 m² g^-1. This unique template-free strategy is very simple in operation and was shown to be generally valid for a variety of multivalent carboxylic acids, including many natural acid molecules. Interestingly, the performance of porous networks in dye removal from ethanol was demonstrated to be superior to activated carbon and mesoporous silica.

Organic acids can crosslink poly(ionic liquid)s into mesoporous polyelectrolyte complexes by Qiang Zhao, Sebastian Soll, Markus Antonietti and Jiayin Yuan, Polym. Chem., 2013, 4, 2432-2435.

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

Nanofibrous scaffolds possessing mechanical properties, porous microstructure, and dimensional similarity to collagen fibers have been used to mimic the natural extracellular matrix (ECM) and are highly relevant for tissue engineering in a number of different applications. Polymeric nanofibers have been fabricated into a variety of constructs and scaffolds using melt- or electrospinning processes. For regenerative medicine applications, the polymeric precursors used to fabricate the nanofiber-based scaffolds should be both biocompatible and biodegradable. Many biodegradable and biocompatible polymers have been widely investigated as fiber and nanofiber precursor materials. Although these degradable polymers meet several of the basic requirements for tissue engineering applications, bioactive molecules to guide cellular behavior and preserve cell phenotype are required for optimal performance.

In this context,  Becker and co-workers described a polymerization method utilizing 4-dibenzocyclooctynol (DIBO) as an initiator for the ring-opening polymerization of 3-caprolactone which yielded an end-functionalized PCL polymer. The DIBO group survived the relatively mild polymerization conditions and offered efficient, orthogonal and biocompatible functionalization opportunities for both the polymer and polymer-derivatized biomaterials. The combination of PCL and DIBO enabled large-scale production of a new type of easily functionalizable nanofiber-based scaffold with versatile regenerative medicine applications.

4-Dibenzocyclooctynol (DIBO) as an initiator for poly(ε-caprolactone): copper-free clickable polymer and nanofiber-based scaffolds by Laurent Chabanne, Stefan Pfirrmann, David J. Lunn and Ian Manners, Polym. Chem., 2013, 4, 2215-2218.

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

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