Template-mediated synthesis of metal-complexing polymers for molecular recognition

The design of synthetic molecules capable of recognizing given chemical entities in a specific and predictable manner is of great fundamental and practical importance. The principal paradigm of the molecular design of such materials involves the preorganization of binding sites of the host system (receptor) around complementary binding sites of the guest molecule (substrate). Wulff and co-workers devised a novel approach to synthesizing substrate-selective polymers that consists of covalent linking of polymerizable groups around a template molecule and subsequent cross-linking polymerization of the resulting assembly. The orientations of the binding sites of the template molecules sculpt the substrate-selective architecture of the templated polymers. Here we report a novel variation of this template polymerization technique to synthesize rigid macroporous polymers containing strategically distributed Cu(II)-iminodiacetate (Cu^(II)IDA) complexes. The resulting polymers exhibit selectivity for bisimidazole "protein analogues" that are not distinguishable by reverse-phase HPLC

Template-mediated synthesis of metal-complexing polymers for molecular recognition

The design of synthetic molecules capable of recognizing given chemical entities in a specific and predictable manner is of great fundamental and practical importance. The principal paradigm of the molecular design of such materials involves the preorganization of binding sites of the host system (receptor) around complementary binding sites of the guest molecule (substrate). Wulff and co-workers devised a novel approach to synthesizing substrate-selective polymers that consists of covalent linking of polymerizable groups around a template molecule and subsequent cross-linking polymerization of the resulting assembly. The orientations of the binding sites of the template molecules sculpt the substrate-selective architecture of the templated polymers. Here we report a novel variation of this template polymerization technique to synthesize rigid macroporous polymers containing strategically distributed Cu(II)-iminodiacetate (Cu^(II)IDA) complexes. The resulting polymers exhibit selectivity for bisimidazole "protein analogues" that are not distinguishable by reverse-phase HPLC

Self-assembled hyaluronan nanocapsules for the intracellular delivery of anticancer drugs

Open Access - This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Te images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. © The Author(s) 2019Preparation of sophisticated delivery systems for nanomedicine applications generally involve multi-step procedures using organic solvents. In this study, we have developed a simple self-assembling process to prepare docetaxel-loaded hyaluronic acid (HA) nanocapsules by using a self-emulsification process without the need of organic solvents, heat or high shear forces. These nanocapsules, which comprise an oily core and a shell consisting of an assembly of surfactants and hydrophobically modified HA, have a mean size of 130 nm, a zeta potential of −20 mV, and exhibit high docetaxel encapsulation efficiency. The nanocapsules exhibited an adequate stability in plasma. Furthermore, in vitro studies performed using A549 lung cancer cells, showed effective intracellular delivery of docetaxel. On the other hand, blank nanocapsules showed very low cytotoxicity. Overall, these results highlight the potential of self-emulsifying HA nanocapsules for intracellular drug delivery.The authors acknowledge Carmen Abuin Redondo for her contribution in the in vitro experimental part. The authors acknowledge financial support from Xunta de Galicia (Competitive Reference Groups-FEDER Funds GRC2013-043). A. Cadete acknowledges her doctoral fellowship from the European Commission (EACEA) under the Nanofar program, Erasmus Mundus Joint Doctorate (EMJD). A. Olivera acknowledges her doctoral fellowship from the Spanish Ministry of Science, Innovation and Universities (grant number BES-2015-071236).info:eu-repo/semantics/publishedVersio

Metal-coordination interactions in the template-mediated synthesis of substrate-selective polymers: recognition of bis(imidazole) substrates by copper(II) iminodiacetate containing polymers

Metal-complexing polymer matrices capable of specific recognition and binding to metal-coordinating substrates have been prepared by template-directed polymerization. The synthesis of these materials involves preorganization of a copper-containing vinyl monomer, copper(II) [N-(4-vinylbenzyl)-imino]diacetic acid (1), with bifunctional bis(imidazole) templates (2-5) of varying geometry and subsequent polymerization with a large excess of ethylene glycol dimethacrylate as the cross-linking agent. Complexation of metal-chelating monomers with the template during polymerization directs the positioning of metal ions in the polymer matrices, while a high degree of cross-linking stabilizes the functional group arrangement. In equilibrium binding experiments with single substrates and selected substrate pairs, the polymers preferentially bind their own templates, with separation factors (α) of 1.17-1.35 and binding constants that range from 1800 to 3800 M^(-1). The capacities and affinities of the polymers for different substrates and ESR spectral analyses of the polymers loaded with substrate suggest a defined arrangement of metal ion sites in the templated materials that is absent in nontemplated polymers. The substrate selectivity likely involves some cooperative two-site coordination of the bis(imidazoles) as well as steric interactions with the binding cavities ("cavity fitting"). This template polymerization strategy is discussed from the viewpoint of designing highly specific abiotic receptors for recognition of delicate and complex biomolecules

Metal-coordination interactions in the template-mediated synthesis of substrate-selective polymers: recognition of bis(imidazole) substrates by copper(II) iminodiacetate containing polymers

Metal-complexing polymer matrices capable of specific recognition and binding to metal-coordinating substrates have been prepared by template-directed polymerization. The synthesis of these materials involves preorganization of a copper-containing vinyl monomer, copper(II) [N-(4-vinylbenzyl)-imino]diacetic acid (1), with bifunctional bis(imidazole) templates (2-5) of varying geometry and subsequent polymerization with a large excess of ethylene glycol dimethacrylate as the cross-linking agent. Complexation of metal-chelating monomers with the template during polymerization directs the positioning of metal ions in the polymer matrices, while a high degree of cross-linking stabilizes the functional group arrangement. In equilibrium binding experiments with single substrates and selected substrate pairs, the polymers preferentially bind their own templates, with separation factors (α) of 1.17-1.35 and binding constants that range from 1800 to 3800 M^(-1). The capacities and affinities of the polymers for different substrates and ESR spectral analyses of the polymers loaded with substrate suggest a defined arrangement of metal ion sites in the templated materials that is absent in nontemplated polymers. The substrate selectivity likely involves some cooperative two-site coordination of the bis(imidazoles) as well as steric interactions with the binding cavities ("cavity fitting"). This template polymerization strategy is discussed from the viewpoint of designing highly specific abiotic receptors for recognition of delicate and complex biomolecules

Hydrogen-bonding-mediated generation of side chain liquid crystalline polymers from complementary nonmesogenic precursors

Liquid crystalline phases in macromolecular assemblies have been generated by utilizing complementary hydrogen-bonding interaction between functional vinyl polymers and rigid aromatic derivatives. While neither of the individual components is mesogenic, the resulting assemblies exhibited liquid crystalline behavior. Poly((2-dimethylamino)ethyl methacrylate) and poly(2-hydroxyethyl methacrylate) were chosen as the functional polymer backbone bearing proton-accepting and proton-donating groups, respectively. As rigid aromatic units, 4-hydroxybiphenyl, trans-4-hydroxystilbene, 4'-methoxy-4-hydroxyazobenzene, and 4-pyridylbenzoate were used. All the polymeric assemblies were obtained as transparent films and they exhibited liquid crystalline properties. Hydrogen-bonding in these assemblies was evident from their FTIR and 13C NMR spectra. The liquid crystalline behavior of these hydrogen-bonded polymeric assemblies was established by DSC, polarizing microscopy, and X-ray diffractometry. Phase diagrams of the mixtures revealed the dependence of the liquid crystalline transitions on the composition of such binary mixtures. Generation of liquid crysalline phases in these hydrogen-bonded polymeric assemblies derived from non-liquid crystalline precursors without the mediation of a flexible spacer is unprecedented. Furthermore, this approach offers a relatively simple route to prepare functional materials with controlled molecular architecture from readily accessible and simpler precursors

Polymeric metal complex catalyzed enantioselective epoxidation of olefins

Spectacular achievements in catalytic asymmetric epoxidation of olefins using chiral Mn(III)-salen complexes have stimulated a great deal of interest in designing polymeric analogs of these complexes and their use as recyclable chiral catalysts. Several strategies have been devised to anchor these chiral catalytic moieties to polymer supports. Techniques of copolymerization of appropriate functional monomers and chemical modification of preformed functional polymers have been utilized to prepare these polymers. Both organic and inorganic polymers have been used as the carriers to immobilize these metal complexes. Results of these investigations are reviewed in this article