ABC type miktoarm star copolymers through combination of controlled polymerization techniques with thiol-ene and azide-alkyne click reactions

Cinnamyl-Modified Polyglycidol/Poly(ε-Caprolactone) Block Copolymer Nanocarriers for Enhanced Encapsulation and Prolonged Release of Cannabidiol

The present study describes the development of novel block copolymer nanocarriers of the phytocannabinoid cannabidiol (CBD), designed to enhance the solubility of the drug in water while achieving high encapsulation efficiency and prolonged drug release. Firstly, a well-defined amphiphilic block copolymer consisting of two outer hydrophilic polyglycidol (PG) blocks and a middle hydrophobic block of poly(ε-caprolactone) bearing pendant cinnamyl moieties (P(CyCL-co-CL)) were synthesized by the click coupling reaction of PG-monoalkyne and P(CyCL-co-CL)-diazide functional macroreagents. A non-modified polyglycidol/poly(ε-caprolactone) amphiphilic block copolymer was obtained as a referent system. Micellar carriers based on the two block copolymers were formed via the solvent evaporation method and loaded with CBD following two different protocols-loading during micelle formation and loading into preformed micelles. The key parameters/characteristics of blank and CBD-loaded micelles such as size, size distribution, zeta potential, molar mass, critical micelle concentration, morphology, and encapsulation efficiency were determined by using dynamic and static multiangle and electrophoretic light scattering, transmission electron microscopy, and atomic force microscopy. Embedding CBD into the micellar carriers affected their hydrodynamic radii to some extent, while the spherical morphology of particles was not changed. The nanoformulation based on the copolymer bearing cinnamyl moieties possessed significantly higher encapsulation efficiency and a slower rate of drug release than the non-modified copolymer. The comparative assessment of the antiproliferative effect of micellar CBD vs. the free drug against the acute myeloid leukemia-derived HL-60 cell line and Sezary Syndrome HUT-78 demonstrated that the newly developed systems have pronounced antitumor activity.

Polymer-Ligated Nanocrystals Enabled by Nonlinear Block Copolymer Nanoreactors: Synthesis, Properties, and Applications

The past several decades have witnessed substantial advances in synthesis and self-assembly of inorganic nanocrystals (NCs) due largely to their size- and shape-dependent properties for use in optics, optoelectronics, catalysis, energy conversion and storage, nanotechnology, and biomedical applications. Among various routes to NCs, the nonlinear block copolymer (BCP) nanoreactor technique has recently emerged as a general yet robust strategy for crafting a rich diversity of NCs of interest with precisely controlled dimensions, compositions, architectures, and surface chemistry. It is notable that nonlinear BCPs are unimolecular micelles, where each block copolymer arm of nonlinear BCP is covalently connected to a central core or polymer backbone. As such, their structures are static and stable, representing a class of functional polymers with complex architecture for directing the synthesis of NCs. In this review, recent progress in synthesizing NCs by capitalizing on two sets of nonlinear BCPs as nanoreactors are discussed. They are star-shaped BCPs for producing 0D spherical nanoparticles, including plain, hollow, and core-shell nanoparticles, and bottlebrush-like BCPs for creating 1D plain and core/shell nanorods (and nanowires) as well as nanotubes. As the surface of these NCs is intimately tethered with the outer blocks of nonlinear BCPs used, they can thus be regarded as polymer-ligated NCs (i.e., hairy NCs). First, the rational design and synthesis of nonlinear BCPs via controlled/living radical polymerizations is introduced. Subsequently, their use as the NC-directing nanoreactors to yield monodisperse nanoparticles and nanorods with judiciously engineered dimensions, compositions, and surface chemistry is examined. Afterward, the intriguing properties of such polymer-ligated NCs, which are found to depend sensitively on their sizes, architectures, and functionalities of surface polymer hairs, are highlighted. Some practical applications of these polymer-ligated NCs for energy conversion and storage and drug delivery are then discussed. Finally, challenges and opportunities in this rapidly evolving field are presented.

Advances in PEG-based ABC terpolymers and their applications

ABC terpolymers are a class of very important polymers because of their expansive molecular topologies and extensive architectures. As block A, poly(ethylene glycol) (PEG) is one of the most principal categories owing to good biocompatibility and wide commercial availability. More importantly, the synthetic approaches of ABC terpolymers using PEG as a macroinitiator are facile and varied. PEG-based ABC terpolymers from design and synthesis to applications are highlighted in this review. Linear, 3-miktoarm, and cyclic polymers as the architecture are separated. The synthetic approaches of PEG-based ABC terpolymers mainly include the sequential polymerization or coupling of polymers. PEG-based ABC terpolymers have wide applications in the fields of drug carriers, gene vectors, templates for the fabrication of inorganic hollow nanospheres, and stabilizers of metal nanoparticles.

Combining Click Reactions for the One-Pot Synthesis of Modular Biomolecule Mimetics

Here, we report on the first combined one-pot use of the two so-called "click reactions": the thiol-ene coupling and the copper-catalyzed alkyne-azide cycloaddition. These reactions were employed in an alternating and one-pot fashion to combine appropriately functionalized monomeric carbohydrate building blocks to create mimics of trisaccharides and tetrasaccharides as single anomers, with only minimal purification necessary. The deprotected oligosaccharide mimics were found to bind both plant lectins and human galectin-3.

Synthesis and Characterization of Polystyrene-Supported Piperazine-Substituted Triazoles by CuAAC and First Evaluation for Metal Ion Extraction

The goal of this work was to synthesize substituted polystyrene for metal extraction and/or depollution by introduction of substituted piperazines as chelatants starting from Merrifield polymer. After transformation of Merrifield’s resin in azidomethyl polystyrene, click-chemistry using copper (I)-catalyzed Huisgen’s reaction (CuAAC) was performed to prepare different polymers grafted with 1,4-triazoles bearing the piperazines, containing an alkyne as the other counterpart in the CuAAC. The polymers were then first tested for their efficiency to remove various metal ions from neutral aqueous solutions (Fe³⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺). The polymers were found to extract Ni²⁺ and Zn²⁺ with low efficiencies ≤40%. For Fe³⁺ and Cu²⁺, the average extraction was around 80%, and for Pb²⁺ around 50%. The global selectivity for these polymers was found to be in the order of Fe³⁺ ≥ Cu²⁺ > Pb²⁺ >> Ni²⁺ > Zn²⁺.

Synthesis of ABB′ and ABC star copolymers via a combination of NMRP and ROP reactions

Well-defined miktoarm star copolymers (ABB′ and ABC) were synthesized via a combination of NMRP and ROP using N-(2-hydroxyethyl)maleimide as the branching molecule.

Dibenzoyldiethylgermane as a visible light photo-reducing agent for CuAAC click reactions

A highly active, versatile and visible light-responsive system for CuAAC click reaction using the dibenzoyldiethylgermane photoinitiator with Cu(ii) has been developed.

Synthesis, Dye Encapsulation, and Highly Efficient Colouring Application of Amphiphilic Hyperbranched Polymers

A novel kind of amphiphilic hyperbranched polymer (AHP), poly(2-(dimethylamino)ethyl methacrylate)-co-polystyrene (HPTAM-co-PS), was synthesized via the combination of reversible addition–fragmentation chain-transfer polymerization and self-condensing vinyl polymerization (RAFT-SCVP). HPTAM-co-PS was functionalized via the highly efficient Menschutkin click reaction, resulting in hyperbranched poly(propargyl quaternary ammonium methacrylate)-co-polystyrene (HPPrAM-co-PS) with a hydrophilic quaternary ammonium salt core and hydrophobic PS shell. The average numbers of dye molecules trapped by each molecule of HPPrAM-co-PS (24.2 kDa) were 24.1 for methyl orange (MO), 22.0 for fluorescein sodium (FS), 24.2 for rose bengal (RB), and 238.4 for Congo red (CR). The polymer–dye complexes show excellent colouring effects for both PS and poly(styrene-b-butadiene-b-styrene) (SBS) membranes; the colour of the membrane containing AHP is very stable and uniform. Our work opens an avenue for the design of efficient dye-colouring additives and for the application of hyperbranched polymers in the field of polymer colouring.

Thiol–ene “click” reactions and recent applications in polymer and materials synthesis: a first update

This contribution serves as an update to a previous review (Polym. Chem.2010,1, 17–36) and highlights recent applications of thiol–ene ‘click’ chemistry as an efficient tool for both polymer/materials synthesis as well as modification.

Constructing star polymersvia modular ligation strategies

Over recent years, modular ligation reactions—some of which adhere to the click criteria—have enabled the synthesis of a variety of star polymers via efficient polymer–polymer conjugations. The copper catalyzed azide–alkyne cycloaddition (CuAAC), Diels–Alder (DA), and Hetero Diels–Alder (HDA) reactions are reviewed here in detail for the facile generation of various macromolecular star topologies.