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[Display omitted] • A novel AEE monomer BDPPA with asymmetric D-A-D' structure was prepared, which has an obvious red-shift emission as compared with PHT and TPE. • The desirable PEG-BD copolymers exhibited excellent biocompatibility and easy cells endocytosis, making them be potential for bioimaging. • Moreover, the effect of D-A-D' structure and ICT effect on the fluorescence property of AEE molecules was revealed. Organic fluorescence dyes with long wavelength emission are attracting people's interests in bioimaging, cells tracing and medical diagnosis due to their many advantages. This contribution exhibited a novel red fluorescent monomer BDPPA with traditional tetraphenylethylene (TPE) and phenothiazine (PHT) as structural units, which showed aggregation-induced emission enhancement (AEE) effects together with the twisted intramolecular charges transfer (TICT) owing to its D-A-D' structure. The maximal emission wavelength of BDPPA located at 592 nm with a shoulder peak at 629 nm. Afterwards, the amphiphilic PEG-BD copolymers was acquired by RAFT polymerization of BDPPA and PEGMA. When the feeding ratio of BDPPA increased from 10.0 % to 20.0 %, the ratio of BDPPA in PEG-BD copolymers correspondingly increased from 9.6 % to 20.9 %. The obtained amphiphilic PEG-BD could self-assemble into fluorescence organic nanoparticles (FONs) with about 150 nm diameter in H 2 O solution. Owing to their TICT effect and D-A-D' structure, both BDPPA and PEG-BD copolymers showed obvious fluorescence in THF solvent, and their intensity firstly decreased and then grew with the increase of water concentration, indicative of the obvious aggregation-induced emission enhancement (AEE). From the calculations of energy quantum, the difference ΔE of BDPPA decreased to 3.09 eV from 3.53 eV of its substrate PHT, which was very favourable for the long wavelength emission and cell imaging. Moreover, due to the long wavelength emission, excellent water solubility and biocompatibility, and AEE effect, the obtained PEG-BD FONs revealed the promising application in biological imaging field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel gradient-like copolymers were synthesized by RAFT polymerization. • Copolymerization of N -vinylsuccinimide with O-cholesteryl (meth)acrylate was studied. • Amphiphilic poly(vinylsuccinamic acid-co-cholesteryl (meth)acrylate)s were obtained. • Stable nanoparticles of 100–400 nm were produced by several techniques. • Irinotecan delivery systems with high loading and inhibitory activity were developed. Today, biocompatible and bioinspired well-defined copolymers with the ability to form nanoparticles are of great interest as potential drug delivery systems. In this study, we report the synthesis of novel biocompatible copolymers from monomers with different activity and capable of forming gradient copolymers by RAFT polymerization. In particular, the copolymerization of N -vinylsuccinimide (VSI) and O -cholesteryl (meth)acrylate (Ch(M)A) mediated by S,S' -dibenzyl trithiocarbonate (DBTTC) has been thoroughly studied by varying the monomer ratio and the ratio of monomer to RAFT agent. Important dependencies such as molecular weight and monomer conversion versus time, and molar fraction of monomer units as a function of monomer conversion were investigated. The obtained copolymers were thoroughly characterized using a number of physicochemical methods such as 1H NMR, 1H–13C HSQC and ATR-IR-spectroscopy, size-exclusion chromatography, static and dynamic light-scattering, as well as thermogravimetric analysis. In addition, the reactivity ratios of VSI and ChMA were determined and the dyad and triad compositions of the copolymers were calculated from the obtained values. The synthesized P(VSI- co -Ch(M)A) were subjected to selective hydrolysis of succinimide ring to convert it into succinamic acid. This approach yields a set of bioinspired amphiphilic copolymers based on N -vinylsuccinamic acid (VSAA) and Ch(M)A. The synthesized series of P(VSI- co- Ch(M)A) and P(VSAA- co -Ch(M)A) were used to obtain nanoparticles by nanoprecipitation or self-assembly via direct dissolution in aqueous medium. In addition, the method of surface hydrolysis of VSI units in pre-formed P(VSI- co- Ch(M)A) nanoparticles was applied to produce nanoparticles with hydrophilic negatively charged surface and enhanced stability. All techniques were optimized to prepare nanoparticles with characteristics suitable for systems considered for drug delivery. Successful loading of the antitumor drug irinotecan into nanoparticles was achieved with high encapsulation efficacies. The storage stability of empty and irinotecan loaded nanoparticles were studied in various media (water, saline solution, serum containing cell culture medium) under room and refrigerator conditions. The developed empty nanoparticles exhibited low rate of uptake by macrophages and low cytotoxicity to irinotecan-sensitive colon cancer cells (Caco-2). In turn, the irinotecan-loaded nanoparticles demonstrated inhibitory activity against Caco-2 cells comparable to the free drug. [ABSTRACT FROM AUTHOR]

This paper provides a review of the literature on the use of Pluronic® triblock copolymers for drug encapsulation over the last 10 years. A special focus is given to the progress of drug delivery systems (e.g. , micelles, liposomes, micro/nanoemulsions, hydrogels and nanogels, and polymersomes and niosomes); the beneficial aspects of Pluronic® triblock copolymers as biological response modifiers and as pharmaceutical additives, adjuvants, and stabilizers, are also discussed. The advantages and limitations encountered in developing site-specific targeting approaches based on Pluronic-based nanostructures in cancer treatment are highlighted, in addition to innovative examples for improving tumor cytotoxicity while reducing side effects. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Amphiphilic core–shell nanoparticles were self-assembled by emulsion polymerization. • Nanoparticle dispersion was tuned by adjusting hydrogen-donors and hydrogen-acceptors. • Particle size was adjusted by regulating hydrogen-donors and hydrogen-acceptors. • Hydrogen bond interactions were weakened with covalent bonds. • The introduction of hydrogen-acceptors promoted the release of active chlorine. Bacterial contamination in water bodies is potentially transmissible to humans, making water bodies a major pathway of bacterial transmission. However, existing hydantoin copolymer nanoparticles did not achieve the regulation of nanoparticle dispersion and particle size by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. To tackle this issue, amphiphilic hydantoin copolymer nanoparticles (P(VBDH-BA-NVP)NPs) were synthesized by modulating hydrogen-donors and hydrogen-acceptors using emulsion polymerization, and amphiphilic N-halamine copolymer nanoparticles (P(ClV-BA-NVP)NPs) were subsequently prepared via chlorination treatment. Impressively, nanoparticle dispersion and particle size were modulated by adjusting the ratio of hydrogen-donors and hydrogen-acceptors. With the increase of nanoparticle dispersion and the decrease of particle size, the active chlorine content was gradually enlarged, and the antibacterial performance was progressively enhanced against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). More importantly, amphiphilic N-halamine copolymer nanoparticles with two-dimensional dispersing (2DD-P(ClV-BA-NVP)NPs) exhibited excellent antibacterial properties, which benefited from the dual coordination of direct contact killing and indirect release killing in aqueous medium. Through designing P(VBDH-BA-NVP)NPs with hydrogen bond interactions, this approach aims to achieve the constitutive relationship between the effective exposure of active sites and the antibacterial effect. [ABSTRACT FROM AUTHOR]

Advances in cryogenic electron microscopy (cryo-EM) enabled routine near-atomic structure determination of membrane proteins, while nanodisc technology has provided a way to provide membrane proteins with a native or native-like lipid environment. After giving a brief history of membrane mimetics, we present example structures of membrane proteins in nanodiscs that revealed information not provided by structures obtained in detergent. We describe how the lipid environment surrounding the membrane protein can be custom designed during nanodisc assembly and how it can be modified after assembly to test functional hypotheses. Because nanodiscs most closely replicate the physiologic environment of membrane proteins and often afford novel mechanistic insights, we propose that nanodiscs ought to become the standard for structural studies on membrane proteins. Single-particle cryo-electron microscopy (cryo-EM) studies of membrane proteins have become routine and often yield structures at near-atomic resolution. Cryo-EM structures of membrane proteins in lipid nanodiscs often yield information not seen in structures obtained with detergent-solubilized proteins. Nanodiscs not only provide a native-like lipid environment for membrane proteins, but also make it possible to custom design and modify most aspects of the lipid bilayer. Because of the facility of generating and imaging nanodiscs by cryo-EM and because of the novel mechanistic insights into membrane protein function they can provide, nanodiscs ought to become the standard for membrane protein structure determination by single-particle cryo-EM. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel bio-based non-isocyanate polyurea (NIPUrea)-acrylate hybrids for sustainable coatings. • Swift and safe aza-Michael modification of NIPUrea enables efficient acrylate incorporation. • Waterborne dispersions offer sterically stabilized films that are fast curable with UV light. Poly(urethane)-acrylate hybrids are often used to yield high-performing fast UV-curable coatings thanks to their highly reactive acrylate moieties. However, they are usually manufactured from toxic and petro-based isocyanate (e.g. isophorone diisocyanate, hexamethylene diisocyanate) monomers and are dispersed in water using toxic volatile neutralization agent (e.g. triethylamine). To tackle those issues, hydrophobic and bio-based non-isocyanate poly(urea) (NIPUrea) blocks have been synthesized and coupled with hydrophilic poly(ethylene glycol) diacrylate (PEGdA) via aza-Michael reaction to yield VOC-free non-ionic waterborne NIPUrea-acrylate dispersions. Those amphiphilic NIPUrea-PEG hybrids enabled the development of low particle-size waterborne dispersions for fast UV curable films (curing time < 1 min) with high gel content (>98 %) and tunable mechanical properties. [ABSTRACT FROM AUTHOR]

• Controlled synthesis of amphiphilic copolymer based on LMA and PEGMA monomers. • Effect of compositional drift in thermal and emulsifier properties. • Interesting bulk rheological properties. • Incorporation of toluene in formed micelles. Evaluation of loading capacity using 2D NMR. In this work we study the synthesis and properties of copolymers constituted of lauryl methacrylate and poly(ethylene glycol) methyl ether methacrylate monomers, prepared by atom transfer radical copolymerization in the entire composition range (with low and high monomer conversion). We propose a description of the copolymer microstructure, and evaluate the composition drift effect in the thermal and solution properties of the obtained copolymers. Nuclear magnetic resonance (NMR) was used to determine the chemical composition of the copolymers, while differential scanning calorimetry and themogravimetric analysis was employed to understand the thermal chracteristics. Rheological studies were conducted to obtain the viscosity and viscoelastic properties that were correlated with thermal transitions at different temperatures. Finally, dynamic light scattering (DLS) and surface tension measurements were used to evaluate the copolymer solution properties. The incorporation of an oil phase in the self-assembled aggregates was evaluated by DLS and characterized by atomic force microscopy, diffusion-ordered spectroscopy NMR and nuclear Overhauser effect NMR spectroscopy. Our results suggest a longer sequence of LMA units in the copolymer chain and a drift effect in the case of high monomer conversions. A clear dependence on copolymer composition and microstructure to disperse an oil phase in water was observed. We believe that these results bring valuable knowledge that advances the field of macrosurfactants as well as their potential applications in oil recovery and other industrial processes. [ABSTRACT FROM AUTHOR]

Cannabis-based therapeutics have gained increasing attention for their potential health benefits; however, the efficient administration of hydrophobic constituents such as Δ9-tetrahydrocannabinol (THC) remains a challenge. This study explores a novel approach employing amphiphilic block copolymers to encapsulate a THC-rich extract to enhance its analgesic effect. The synthesis of amphiphilic block copolymers involves sequential ring-opening polymerization of caprolactone and a cyclic carbonate with pedant alkyne moieties. This is followed by an alkyne/azide click reaction with fatty acid derivatives. These copolymers are used to encapsulate the THC-rich extract. These extract-loaded micelles exhibit nanometric sizes, uniform distribution, and high colloidal stability in simulated gastrointestinal fluids. The release kinetic assessment of THC from the micelles displays controlled and sustained profiles, which are influenced by the hydrophobic nature of the copolymer core. In vivo evaluations using a murine model revealed the safety of micellar formulations, with minimal impact on behavior and organ health. Remarkably, micellar systems demonstrated prolonged analgesic effects in both mechanical and chemical pain models, outperforming nonencapsulated THC. This study introduces a pioneering approach to cannabis-based analgesics with prolonged activity, harnessing the potential of the tailored design of amphiphilic block copolymers to enhance the delivery and efficacy of hydrophobic cannabinoids. [Display omitted] • Block copolymers containing fatty acid derivatives were synthesized. • The in vivo analgesic activity of a cannabis derivative was enhanced. • Amphiphilic copolymers containing fatty acid are promissory vehicles for cannabinoids. [ABSTRACT FROM AUTHOR]

Abstract Dimanganese decacarbonyl (Mn 2 (CO) 10) and alkyl halide combination has unique visible light radical generating property which is useful in the fabrication of many complex macromolecular structures. Herein, we present a generic simple and rapid synthetic approach for the preparation amphiphilic hyperbranched macromolecular structures with controlled branching density and hydrophilicity. The method is based on the visible light induced self-condensing vinyl copolymerization of methyl methacrylate (MMA), 2-(2-bromoisobutryloxy)ethyl methacrylate (BIBEM) and poly(ethylene glycol) methyl ether methacrylate as monomer, inimer and hydrophilic comonomer, respectively, in the presence of Mn 2 (CO) 10. The resulting polymers possess both hydrophobic and hydrophilic sequences offering many potential bio applications such as controlled drug delivery and release. Moreover, the resulting polymers contain also unreacted bromide groups in the final structure which allow postfunctionalization through copper(I)-catalyzed alkyne-azide cycloaddition "click" reactions. Graphical abstract Image Highlights • A simple and rapid photopolymerization route for the synthesis of hyperbranched amphiphilic copolymers. • One pot, one step, mild and green conditions. • Controlled branching density and hydrophilicity. [ABSTRACT FROM AUTHOR]

The synthesis and aqueous solution properties of copolymers comprised of N - vinylpyrrolidone (NVP) and vinyl laurate (VL) with three different architectures is reported. By using reversible addition-fragmentation chain-transfer (RAFT) polymerization, statistical, forced gradient, and block copolymers were synthesized with varying compositions and molecular weights. Surface tension, critical micelle concentrations (CMCs) and micelle size were determined, and related to copolymer composition, molecular weight and architecture. It was observed that more block-like polymer architectures produced from the block copolymerizations and forced gradient copolymerizations were likely to self-assemble in solution, indicating that the degree and placement of the hydrophilic (NVP) and hydrophobic (VL) monomer units are important in predicting solution behavior of such copolymers. [ABSTRACT FROM AUTHOR]

Amphiphilic copolymers based on renewable resources were involved as emulsifiers to prepare transparent terpene-in-water nanoemulsions. The amphiphilic copolymers are composed of hydrophobically modified poly(acrylic acid) (HMPAA) grafted with different fractions of hydrophobic bio-based tetrahydrogeraniol (THG) side chains. The well-defined PAA were synthesized by reversible addition fragmentation transfer (RAFT) polymerization in order to tune the number-average molar mass of the initial PAA. The self-assembly in aqueous solution of the HMPAA copolymers was investigated through the measurement of their critical aggregation concentration by viscometry, tensiometry, dynamic light scattering and the determination of their aggregation number by static light scattering. Series of oil-in-water nanoemulsions using dihydromyrcenol (DHM) terpene as dispersed phase and PAA-THG as emulsifier were prepared with different PAA-THG/DHM weight ratios and DHM/water weight ratios. The level of transparency of the emulsions was monitored though the transmittance value measured at 600 nm and the measurements of the hydrodynamic diameter of droplets by dynamic light scattering. This study highlights that the structure of the PAA x -THG y is a key parameter to prepare terpene-in-water nanoemulsions with the required high level of transparency. The optimised structure of the emulsifier consists in a moderate degree of polymerization of PAA backbone ( DP ‾ n ,PAA ≤ 180 ) along with an intermediate average degree of substitution in hydrophobic THG side chains (13 ≤ DS ‾ ≤ 32). [ABSTRACT FROM AUTHOR]

Background Mimicking cell membranes by simple models based on the reconstitution of membrane proteins in lipid bilayers represents a straightforward approach to understand biological function of these proteins. This biomimetic strategy has been extended to synthetic membranes that have advantages in terms of chemical and mechanical stability, thus providing more robust hybrid membranes. Scope of the review We present here how membrane proteins and biopores have been inserted both in the membrane of nanosized and microsized compartments, and in planar membranes under various conditions. Such bio-hybrid membranes have new properties (as for example, permeability to ions/molecules), and functionality depending on the specificity of the inserted biomolecules. Interestingly, membrane proteins can be functionally inserted in synthetic membranes provided these have appropriate properties to overcome the high hydrophobic mismatch between the size of the biomolecule and the membrane thickness. Major conclusion Functional insertion of membrane proteins and biopores in synthetic membranes of compartments or in planar membranes is possible by an appropriate selection of the amphiphilic copolymers, and conditions of the self-assembly process. These hybrid membranes have new properties and functionality based on the specificity of the biomolecules and the nature of the synthetic membranes. General significance Bio-hybrid membranes represent new solutions for the development of nanoreactors, artificial organelles or active surfaces/membranes that, by further gaining in complexity and functionality, will promote translational applications. This article is part of a Special Issue entitled: Lipid order/lipid defects and lipid-control of protein activity edited by Dirk Schneider. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hydroxyl-functionalized isotactic polypropylene was synthesized via solution polymerization and grafted onto alternating styrene- co -maleic anhydride copolymer through transesterification reaction. • The amphiphilic graft-copolymers with varying comonomers content were obtained either via solution process or reactive extrusion. • All the graft-copolymers and their precursors were analyzed in terms of molecular structure as well as thermal properties. The copolymers were used as bitumen modifier to verify their suitability for road constructions. • The bulk and rheological properties of the polymer modified bitumen samples were evaluated together with their morphology and nanomechanical properties. High-temperature Performance Grade limits of the samples were determined. Here we demonstrate the application of hydroxyl-functionalized propylene-based copolymers, poly(propylene- co -1-hexene- co -10-undecen-1-ol) (FPP) and poly(styrene- co -maleic anhydride) (SMA) graft copolymers derived thereof, poly(propylene- co -1-hexene- graft -styrene- co -maleic anhydride) (FPP- g -SMA) as bitumen modifiers. The FPP samples were synthesized via solution copolymerization, while FPP- g -SMA products were obtained via transesterification of FPP with SMA either in solution or by a melt-grafting process. FPP -g- SMA modifiers prepared in solution, having a SMA content of around 30 wt%, performed very well as compatibilizer for bitumen, generating a polymer-modified compositions with a uniform morphology and improved nanomechanical properties, storage stability, rheological properties and high-temperature performance as compared to neat bitumen samples. [ABSTRACT FROM AUTHOR]

Curcumin (Cur), an antioxidant molecule, has multiple medicinal properties and displays therapeutic values. However, in some functional food applications, the incorporation of Cur is limited because of its poor solubility and inherent physicochemical instability. Herein, to address these issues, PEGylated poly (trimethylene carbonate) (MPEG-PTMC) was used as the polymeric carrier for fabricating the Cur loaded nanoparticles (MPEG-PTMC@Cur NPs). The MPEG-PTMC@Cur NPs had an average size of ∼130 nm. Importantly, after being incorporated in MPEG-PTMC@Cur NPs, the photochemical stability of Cur was significantly enhanced. The degradation rate of Cur was only about 15%. Furthermore, the MPEG-PTMC@Cur NPs exhibited improved DPPH scavenging ability (SC 25 = 14.40 μg/mL) compared with that of the free Cur (SC 25 > 30 μg/mL). Importantly, the pharmacokinetic study demonstrated that the oral relative bioavailability of MPEG-PTMC@Cur NPs was significantly improved. All these results support that MPEG-PTMC@Cur NPs could be an effective delivery system for Cur. [Display omitted] • MPEG-PTMC was used as the polymeric carrier for fabricating the Cur loaded nanoparticles. • After being incorporated in MPEG-PTMC@Cur NPs, the photochemical stability of Cur was significantly enhanced. • The MPEG-PTMC@Cur NPs possessed superior antioxidant activities compared with that of free Cur. [ABSTRACT FROM AUTHOR]

New cis -bis[ N -(2-nitroxyethyl)isonicotinamide- N ]platinum(iv) tetrachloride hybrid materials were obtained via its solubilization by nanoparticles of N -vinylpyrrolidone copolymer with dimethacrylates and characterized. The materials containing 2% of PtIV complex cause a cytotoxic effect on the tumor A-172 cells; IC50 values were ca. 106 μm after incubation for 48 h. [ABSTRACT FROM AUTHOR]

Nitroxide-containing amphiphilic polymers for therapeutic use were prepared in two-step procedure. Firstly, amphiphilic copolymers composed of hydrophobic poly(n -butyl acrylate) (P n BA) and hydrophilic poly[oligo(ethylene glycol) methyl ether acrylate] (POEGA) or poly(2-hydroxyethyl acrylate) (PHEA) were synthesized by simplified electrochemically mediated atom transfer radical polymerization (se ATRP). Due to the precisely-controlled structure of each polymer block proved by narrow dispersity (M w / M n < 1.19), chain-end halide functionality of macromolecules was preserved. Therefore, it was possible to efficiently convert the halide atom at the end of the chain to stable radicals via the amination of the polymer with 4-amino-2,2,6,6-tetrametylopiperydynyloksyl (4-amino-TEMPO, 4-AT). The prepared polymers are able to self-assemble in an aqueous solution into micelles with a hydrodynamic diameter of approximately 31 nm measured by dynamic light scattering (DLS) analysis. The susceptibility of the prepared micelles for biomedical applications was studied by evaluation of the effect on erythrocytes and fibroblasts and their antioxidant properties by testing of inhibition of oxidation reactions – oxidation of dihydrorhodamine 123 (DHR 123), induced by biologically relevant oxidants. The antioxidant effects of polymeric micelles were compared with those of free 4-AT. Prepared TEMPO-containing micelles exhibited biocompatibility in interaction with human erythrocytes and fibroblasts and exerted antioxidant effects. Therefore, the micelles are potentially good candidates for in vivo applications. [Display omitted] • Amphiphilic copolymers with highly preserved chain-end functionality were provided by se ATRP concept. • The precisely-controlled structure of each polymer block enables post-modification with 4-amino-TEMPO. • Polymeric micelles showed satisfactory biocompatibility and exerted antioxidant effects. • Nitroxide-containing polymer-based micelles have great potential for therapeutic use. [ABSTRACT FROM AUTHOR]

We report the computational analysis, synthesis and characterization of folate functionalized poly(styrene- alt -maleic anhydride), PSMA for drug delivery purpose. The selection of the proper linker between the polymer and the folic acid group was performed before conducting the synthesis using Density Functional Theory (DFT). The computational results showed the bio-degradable linker 2, 4-diaminobutyric acid, DABA as a good candidate allowing flexibility of the folic acid group while maintaining the pH sensitivity of PSMA, used as a trigger for drug release. The synthesis was subsequently carried out in multi-step experimental procedures. The functionalized polymer was characterized using InfraRed spectroscopy, Nuclear Magnetic Resonance and Dynamic Light Scattering confirming both the chemical structure and the pH responsiveness of PSMA-DABA-Folate polymers. This study provides an excellent example of how computational chemistry can be used in selection process for the functional materials and product characterization. The pH sensitive polymers are expected to be used in delivering anti-cancer drugs to solid tumors with overly expressed folic acid receptors. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of Au and Ag nanoparticles prepared by direct reaction between poly(ethylene glycol)–poly(ε-caprolactone) (PEG–PCL) block copolymers and metal precursors in DMSO at 343 K. Special attention is devoted to the structural and molecular weight effects on nanoparticle synthesis to establish general correlations between the experimental parameters and the characteristics of the obtained nanoparticles. The noble metal nanoparticles were characterized by transmission electronic microscopy (TEM), dynamic light scattering (DLS), UV–visible spectroscopy, zeta potential (ZP) and FT-IR techniques. The shape and size of the obtained nanoparticles primarily depend mainly on the chemical structure and composition (PEG–PCL) of the copolymers used in the synthesis. From density functional theory (DFT), the chemical groups responsible for metal salt reduction and stabilization of the nanoparticles have been represented using simple models. The possible solvent effects were also considered by incorporation of a polarizable continuum model (PCM) into the calculations. [ABSTRACT FROM AUTHOR]

Poly(ethylene oxide)- block -poly(methyl methacrylate) amphiphilic copolymers were prepared via electrochemically mediated atom transfer radical polymerization ( e ATRP) utilizing only 50 ppm of Cu II complex, rather than previously reported concentrations of catalyst of ca. 1,000–30,000 ppm. The copolymers were also prepared via a simplified electrochemically mediated ATRP ( se ATRP) procedure utilizing an aluminum wire sacrificial anode as a counter electrode, which was directly immersed into the reaction flask, without the need of its separation. This se ATRP system works under both potentiostatic and galvanostatic conditions. In each case the polymerization results showed similar molecular weight evolution while maintaining a narrow molecular weight distribution throughout the reactions. The successful chain extension and formation of block copolymers confirmed the living nature of the poly(alkyl methacrylates) prepared by e ATRP and se ATRP. [ABSTRACT FROM AUTHOR]

Atom Transfer Radical Polymerization (ATRP) and Ring-Opening Polymerization (ROP) were combined to synthesize diblock environmental friendly poly(ϵ-caprolactone)-block-poly(methyl ether diethylene glycol methacrylate) (PCL- b -PMEO 2 MA) through a sequential two-step strategy. These PCL- b -PMEO 2 MA copolymers were produced using 2-hydroxyethyl-2-bromoisobutyrate as bifunctional initiator. In the first step, ϵ-caprolactone was initiated by the hydroxyl group of this particular initiator. Tin octoate, zinc triflate and bismuth triflate were tested as non-toxic catalysts to obtain α-bromide–ω-hydroxy bifunctional PCL macroinitiator. Secondly, the controlled ATRP of MEO 2 MA was tuned from the same bifunctional initiator. Finally, PCL- b -PMEO 2 MA were produced by carrying out ATRP of MEO 2 MA from PCL macroinitiator. Preliminary data on self-assembly of such thermo-sensitive PCL- b -PMEO 2 MA in aqueous phase are given. [ABSTRACT FROM AUTHOR]

Microbial biofilms are known to support a number of human infections, including those related to medical devices. This work is focused on the development of novel dual-function amphiphilic random copolymers to be employed as coatings for medical devices. Particularly, copolymers were obtained by polymerization of an antimicrobial cationic monomer (bearing tertiary amine) and an antioxidant and antimicrobial hydrophobic monomer (containing hydroxytyrosol, HTy). To obtain copolymers with various amphiphilic balance, different molar ratios of the two monomers were used. 1 H NMR and DSC analyses evidenced that HTy aromatic rings are able to interact with each other leading to a supra-macromolecular re-arrangement and decrease the copolymer size in water. All copolymers showed good antioxidant activity and Fe 2+ chelating ability. Cytotoxicity and hemolytic tests evidenced that the amphiphilic balance, cationic charge density and polymer size in solution are key determinants for polymer biocompatibility. As for the antimicrobial properties, the lowest minimal inhibitory concentration (MIC = 40 μg/mL) against Staphylococcus epidermidis was shown by the water-soluble copolymer having the highest HTy molar content (0.3). This copolymer layered onto catheter surfaces was also able to prevent staphylococcal adhesion. This approach permits not only prevention of biofilm infections but also reduction of the risk of emergence of drug-resistant bacteria. Indeed, the combination of two active compounds in the same polymer can provide a synergistic action against biofilms and suppress reactive species oxygen (ROS), known to promote the occurrence of antibiotic resistance. [ABSTRACT FROM AUTHOR]

Casein-based emulsion for film former was innovatively prepared via emulsifier-free emulsion polymerization by employing self-made amphiphilic copolymers (A m B n C o ) as the stabilizer. Structure of A m B n C o was confirmed by 1 H NMR spectrometry. Stability of the as-prepared emulsion in different concentrations of A m B n C o was evaluated by measuring their droplet size, microstructure and viscosity. The results indicated that the obtained particles were 40–50 nm in size with uniform size distribution, and exhibited obvious core–shell structure. The emulsion containing 1.0 wt% of A m B n C o presented superior storage stability. [ABSTRACT FROM AUTHOR]

Polymeric micelles functionalized with folate conjugated bovine serum albumin (FA-BSA) and loaded with superparamagnetic iron oxide nanoparticles (SPIONs) are investigated as a specific contrast agent for tumor targeting and magnetic resonance imaging (MRI) in vitro and in vivo . The SPIONs-loaded polymeric micelles are produced by self-assembly of amphiphilic poly(HFMA-co-MOTAC)-g-PEGMA copolymers and oleic acid modified Fe 3 O 4 nanoparticles and functionalized with FA-BSA by electrostatic interaction. The FA-BSA modified magnetic micelles have a hydrodynamic diameter of 196.1 nm, saturation magnetization of 5.5 emu/g, and transverse relaxivity of 167.0 mM −1 S −1 . In vitro MR imaging, Prussian blue staining, and intracellular iron determination studies demonstrate that the folate-functionalized magnetic micelles have larger cellular uptake against the folate-receptor positive hepatoma cells Bel-7402 than the unmodified magnetic micelles. In vivo MR imaging conducted on nude mice bearing the Bel-7402 xenografts after bolus intravenous administration reveals excellent tumor targeting and MR imaging capabilities, especially at 24 h post-injection. These findings suggest the potential of FA-BSA modified magnetic micelles as targeting MRI probe in tumor detection. [ABSTRACT FROM AUTHOR]

Binary and ternary segmented polyurethanes (SPU) based on low molar mass (2 kDa) homopolymers – poly(ethylene glycol), poly( l -lactide) and poly(trimethylene carbonate) (PEG, PLLA and PTMC, respectively) – and 2,4-toluene diisocyanate were synthesized using 1,4-butanediol and dibutyltin dilaureate as the chain extender and catalyst, respectively. Rigorous control of the OH/NCO stoichiometry and temperature allowed the synthesis of sixteen uncrosslinked polyurethanes with modulated compositions and properties. The molecular characterizations of the SPUs were performed using 1 H NMR and GPC, and the thermal, dynamic mechanical and morphological features were investigated using DSC, DMTA and AFM, respectively. The blocks were randomly distributed in the polymer chains, which resulted in suppression of the crystallization of the blocks in most of the SPUs. The binary and ternary SPUs are heterogeneous, presenting morphologies of dispersed phase in a matrix, whose compositions depend on the global composition. The hydrophilicity of the SPUs were evaluated using water swelling experiments, and the hydrophilic/hydrophobic balance of the SPUs can be controlled by altering the composition to achieve a completely water soluble SPU (in PEG-rich SPUs), a higher water uptake capability, resulting in a hydrogel (intermediate composition), or a non-swellable polymer (PLLA-PTMC binary SPUs). The dependence of water uptake on temperature was observed mainly in PEG-rich SPUs. The intrinsic properties of each block, such as the hydrophilicity of PEG, stiffness of PLLA and elasticity of PTMC, are combined and modulated in the SPUs. PTMC confers unique properties to ternary SPUs owing to its partial miscibility with both PEG and PLLA. [ABSTRACT FROM AUTHOR]

In this work, TiO 2 nanoparticles were dispersed and stabilized in water using a novel type of dispersant based on tailor-made amphiphilic block copolymers of poly(ethylene glycol)-block-poly(4-vinyl pyridine) (mPEG- b -P4VP) prepared by atom transfer radical polymerization (ATRP). The performance of this new block copolymer as dispersant was compared to a polyelectrolyte dispersant commonly used for TiO 2 , sodium salt of polyacrylic acid (Na-PAA). The effect of dispersion technique and type and amount of dispersant on deagglomeration and stability of the TiO 2 aqueous suspensions were studied. After incorporation in a standard waterborne acrylic varnish formulation, dry film transparency, photocatalytic activity, and nanoparticle cluster size were also evaluated. The results show that mPEG- b -P4VP copolymer with appropriate block lengths can have a better performance than Na-PAA in terms of aqueous dispersion stabilization and cluster size reduction in the acrylic matrix. This translates into higher film transparency and photocatalytic performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • RAFT polymerization of well-defined coumarin bearing amphiphilic copolymers. • Coumarin functionalized unique amphiphilic copolymers as repeating units on the chain. • Temperature responsive Pluronic F127 with light-responsive amphiphilic copolymers. • Designing mechanically strong injectable PF127 hydrogels. Temperature responsive Pluronic F127 micelles were combined with light-responsive coumarin bearing amphiphilic copolymers to obtain both mechanically strong and injectable gels. For this purpose two monomers, 7-(2-methacryloyloxyethoxy)-4-methylcoumarin (CEMA) and 7-methacryloyloxy-4-methylcoumarin (CMA), were synthesized and further polymerized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Well-defined amphiphilic diblock terpolymers were obtained by using preliminarily synthesized polyethylene glycol (PEG) based macroRAFT agent. The structures of copolymers were confirmed with proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier-transform infrared (FT-IR) spectroscopy and gel permeation chromatography (GPC) analyses. Amphiphilic diblock terpolymers self-assembled into micelles in aqueous solution spontaneously and crosslinking of the micelle cores through the photodimerization of coumarin groups under UV irradiation at 350 nm was examined by UV spectroscopy. Hydrogels were prepared using two different methods, PF127-Mx gels formed using polymer micelle solutions with PF127 solid and PF127-Px gels formed by mixing solid polymers with 20 % F127 solution. Upon characterization of hydrogels via dynamic light scattering (DLS) and transition electron microscope (TEM), rheological properties of the gels were evaluated as a function of temperature, composition, UV exposure time, strain and frequency. Injectability tests of hydrogel systems were performed on a texture analyzer and all the formulations were found in the injectable range. The study reveals that hydrogels based on combination of PF127 and coumarin functional terpolymer amphiphiles hold great potential as injectable biomaterials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Brush copolymer analogues of PEG-PLA copolymers were produced via ATRP or ARGET ATRP. • Functionalization of either block was achieved via copolymerization. • Resulting nanoparticles have tunable stability and appropriate size/polydispersity. • High drug loading is achievable with hydrophobic drug payloads (>96% encapsulation) PL(G)A-PEG block polymers have been widely used in a variety of drug delivery applications but are inherently limited in terms of their capacity for functionalization and thus customization to specific delivery tasks. Herein, we report synthetically tunable and functionalizable brush co-polymer analogues of conventional PL(G)A-PEG polymers fabricated via atom transfer radical polymerization (ATRP) of methacrylate-based co-monomers with oligo(lactic acid) side chains in the hydrophobic block and oligo(ethylene glycol) side chains in the hydrophilic block. Block co-polymers prepared by varying the molecular weights of each block, the functionality of either block (via functional monomer copolymerization), as well as the number of lactic acid repeat units in the hydrophobic block were subsequently used to fabricate nanoparticles with sizes of 100–500 nm and tunable degradation rates via flash nanoprecipitation. The resulting nanoparticles exhibited high colloidal stability (consistent with the dense brush-like POEGMA interface), favorable in vitro cytocompatibility, and the capacity for effective drug loading (>96% encapsulation efficiency for paclitaxel and 41% even for the hydrophilic therapeutic doxorubicin hydrochloride). Furthermore, functionalization of the hydrophobic POLAMA block with methacrylic acid residues enabled controlled dissolution of the nanoparticle over time, offering potential to tune drug release via an alternative mechanism not readily accessible with conventional PLA-PEG-based block copolymers. Combining these properties with the flexible chemical compositions and the generally recognized as safe degradation properties of the brush polymer analogues, POLAMA- b- POEGMA polymers represent a highly versatile platform for nanoparticle-based drug delivery applications. [ABSTRACT FROM AUTHOR]

Abstract: Hypericin (HY) is a naturally-occurring, potent photosensitizer. However, its lipophilicity limits its therapeutic applications. Our attempt is, thus, to develop a biodegradable nanocarrier for hypericin capable of preserving its antibacterial photoactivity. Amphiphilic block copolymers were synthesized to prepare hypericin-laden nanoparticles (HY-NPs). The antimicrobial photoactivity of HY-NPs was assessed; in vitro against biofilm and planktonic cells of methicillin resistant Staphylococcus aureus (MRSA) clinical isolates and in vivo on infected wounds in rats. Nanoparticles of 45nm in diameter ensured higher amounts of reactive oxygen species upon irradiation. HY-NPs demonstrated superior inhibition of biofilm over planktonic cells. In vivo wound healing studies in rats revealed faster healing, better epithelialization, keratinization and development of collagen fibers when HY-NPs were applied. Determination of growth factors and inflammatory mediators in the wound area confirmed superior healing potential of nanoencapsulated hypericin suggesting that hypericin can join the era of antibiotic-free antimicrobial therapy. [Copyright &y& Elsevier]

Highlights: [•] Oligocaprolactone chains are grafted onto starch backbone via CuAAC click chemistry. [•] Azido-functionalized oligocaprolactones are synthesized by functional ROP. [•] Propargylated starch and PCL-g-starch are characterized by NMR and XPS spectroscopy. [•] Swelling behavior of amphiphilic copolymers in interpreted in terms of solubility parameters. [•] The amphiphilic copolymers present the capacity to organize in aggregates in aqueous solutions. [ABSTRACT FROM AUTHOR]

Abstract: Experimental conditions for the synthesis of poly(ε-caprolatone)-graft-poly(vinyl alcohol) (PCL-g-PVA) and poly(l-lactide)-graft-poly(vinyl alcohol) (PLLA-g-PVA) via a PVA/MgH2 macroinitiator were optimized. Heat stability of PVA (99% hydrolyzed) in l-lactide (L-LA) melt was studied by DSC, TGA to lower the reaction temperature and time in order to avoid degradation. Thus, no degradation of copolymers occurred and 13C NMR study showed that l-lactide was incorporated in graft chains as isotactic poly(l-lactide) without racemisation for 140–160°C, up to 25h, L-LA/PVA ratio in the range 3–12. Such synthesis using non-toxic catalyst and reactants in a solvent-free medium can be described as environment-friendly. Amphiphilic behavior of copolymers was studied in aqueous solution according to their chemical structures: critical micelle concentration CMC (0.03–0.5gL−1), average diameter of micelles (80–150nm), surface tension γ CMC (46–63mNm−1), hydrophilic to lipophilic balance HLB (Griffin definition 4–7), and also from cast films: surface energy γ s (36–50mJm−2). This environment-friendly process is suitable for the use of graft PVA copolymers in biomedical area for investigations under micelle applications. [Copyright &y& Elsevier]

Abstract: Amphiphilic copolymers based on the copolymerization of hydrophilic and hydrophobic moieties offer versatility in various biomedical material applications. Here, a new biocompatible copolymer of dextran-graft-polybutylmethacrylate is synthesized for the coating of metallic endovascular stents. Coating of metallic surfaces is performed and analyzed by X-ray photoelectron spectroscopy, attenuated total reflection Fourier transform infrared spectroscopy, contact angle measurement, atomic force microscopy and scanning electron microscopy before and after deformation corresponding to stent deployment by a balloon catheter. In the conditions described here, the resulting coating is smooth and uniform with neither cracks nor detachment after stent expansion. Interestingly, surfaces coated with the copolymer greatly improve in vitro adhesion and growth of endothelial cells. This copolymer provides new opportunities for implanted biomaterials. [Copyright &y& Elsevier]

Abstract: One of the major industrial uses of lipases is as active agent in bio-based washing formulations. Current methods to improve lipase stability in detergent formulations usually entail a decrease in the enzymatic activity, thus lowering the general performance of the detergent. This work proposes an alternative approach for enzyme stabilization and activity enhancement based on the application of amphiphilic light-harvesting copolymers, called here photozymes. The biopolymer-based chitosan-Rose Bengal and the synthetic poly(SSS0.75–co-VBA0.24–co-VB/hematoporphyrin0.01) photozymes were used as boosting agents in washing formulations containing lipase. Organic stain removal from textiles was improved by 33% at 25°C. This cleaning enhancement was attributed to the increase of lipase activity due to interfacial activation in presence of photozymes, along with prevention of dirt re-deposition on the cleaned surfaces. Although both photozymes improved lipase activity, chitosan-Rose Bengal photozyme performed better at pHs above 9 while at pHs below this value SSS–VBA–VB/HP was the most effective. Dynamic light scattering, zeta-potential measurements, fluorescence spectroscopy and FRET experiments confirmed the pseudomicellar conformation and hosting capacity of the photozymes in aqueous media leading to improved dirt solubilization and emulsification. Moreover, the photocatalytic activity of the photozyme allowed for a de-coloration of the waste washing liquor upon UV irradiation. [Copyright &y& Elsevier]

Abstract: Binary complexes of cationic polymers and DNA were used commonly for DNA delivery, whereas, the excess cationic charge of the binary complexes mainly leads to high toxicity and unstability in vivo. In this paper, ternary complexes by coating polyglutamic acid-graft-poly(ethylene glycol)(PGA-g-mPEG) onto binary complexes of polycaprolactone-graft-poly(N,N-dimethylaminoethyl methacrylate) (PCL-g-PDMAEMA) nanoparticles (NPs)/DNA were firstly developed for effective and targeted gene delivery. The coating of PGA-g-mPEG was able to decrease the zeta potential of the nano-sized DNA complexes nearly to electroneutrality without interferring with DNA condensation ability. As a result, the stability, the escape ability from endosomes and the transfection efficiency of the complexes were enhanced. The ternary complexes of PCL-g-PDMAEMA NPs/DNA/PGA-g-mPEG demonstrated lower cytotoxicity in CCK-8 measurements and higher gene transfection efficiency than the binary complexes in vitro. In addition, Lactate dehydrogenase (LDH) assay was performed to quantify the membrane-damaging effects of the complexes, which is consistent with the conclusion of CCK-8 measurement for cytotoxicity assay. The in vivo imaging measurement and histochemical analysis of tumor sessions confirmed that the intravenous administration of the ternary complexes with red fluorescent protein (RFP) as payload led to protein expression in tumor, which was further enhanced by the targeted coating of PGA-g-PEG-folate. [Copyright &y& Elsevier]

Abstract: In this study we present our efforts to homo- and co-polymerize, using group transfer polymerization (GTP), a dialkyl diester of itaconic acid, a naturally-derived unsaturated dicarboxylic acid. The monomer employed, di(n-butyl) itaconate (DBI), did not seem to polymerize by GTP to high conversion, but it displayed the remarkable ability to contribute to the polymer 1–2 units, suggesting that it would make a good end-functionalizing reagent for GTP. This was demonstrated by preparing by GTP hydrophilic homopolymers, and in situ adding to them DBI which is hydrophobic. The thus-obtained amphiphilic end-functionalized copolymers formed in water small micelles, whose aggregation numbers and radii of gyration were characterized using small-angle neutron scattering. [Copyright &y& Elsevier]

Abstract: A group of amphiphilic cationic polymers, methoxy polyethylene glycol-block-(polycaprolactone-graft-poly(2-(dimethylamino)ethyl methacrylate)) (PECD), were synthesized by combining ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) methods to form nanoparticles (NPs). The structures of these amphiphilic cationic polymers were characterized by 1H NMR measurement. The PECD NPs have hydrophobic cores covered with hydrophilic PEG and cationic PDMAEMA chains. These self-assembly nanoparticles were characterized by dynamic light scattering (DLS) technique. PECD NPs can effectively condense DNA to form compact complexes of the size 65–160 nm suitable for gene delivery. The in vitro gene transfection studies of HeLa and HepG2 cells show that PECD NPs have better transfection efficiency compared to polyethylenimine (PEI) and Lipofectamine 2000 at low dose (N/P = 5). The cytotoxicity result shows that PECD NPs/DNA complexes at the optimal N/P ratio for transfection have comparable toxicity with PEI and Lipofectamine. These results indicate that PECD NPs have a great potential to be used as efficient polymeric carriers for gene transfection. [ABSTRACT FROM AUTHOR]

Abstract: Amphiphilic block copolymers are attracting increasing interest in the field of gene therapy, especially for transfection of striated muscles. However, little is known about the parameters affecting their transfection efficiency in vivo. These copolymers can self-assemble as micelles in certain conditions. Since micellization strongly depends on the temperature and ionic content of the preparation medium, the present paper aimed at investigating the influence of these parameters in the context of gene delivery. We first assessed the micellization of pluronic L64 and tetronic 304 at various temperatures in water, saline or Tyrode''s salts solution. Pluronic L64 can form micelles at temperatures above 37 °C in water or at 37 °C in the Tyrode''s salts solution, in the range of concentration investigated. For tetronic 304, CMC was found to be far below the concentrations used to transfer DNA. Pluronic L64 interacted with DNA only in the presence of micelles. Moreover, in vivo evaluation demonstrated that significantly improved transfection efficiency was obtained at 37 °C in Tyrode''s salts solution for pluronic L64 based formulations, compared to 4 °C and 20 °C. Such differences were not recorded with tetronic 304. Finally, optimized formulations of both tetronic 304 and pluronic L64 were able to mediate efficient transfection in dystrophic muscles. [Copyright &y& Elsevier]

Abstract: In this paper three copolymers of polyhydroxyethylaspartamide (PHEA), bearing in the side chains polyethylene glycol (PEG) and/or hexadecylamine (C16) (PHEA-PEG, PHEA-PEG-C16 and PHEA-C16 respectively) have been studied as potential colloidal drug carriers for ocular drug delivery. The physical characterization of all three PHEA derivatives, using the Langmuir trough (LT) and micellar affinity capillary electrophoresis (MACE) techniques allowed to assume that whereas alone PHEA backbone is an inert polymer with respect to the interactions with lipid membranes and drug complexation, when PHEA chains are grafted with long alkyl chains like C16 or in combination C16 chains and hydrophilic chains like PEG, copolymers with lipid membrane interaction ability and drug complexation capability are obtained. In vitro permeability studies performed on primary cultured rabbit conjunctival and corneal epithelia cells, using PHEA-C16 and PHEA-PEG-C16 as micelle carriers for netilmicin sulphate, dexamethasone alcohol and dexamethasone phosphate, demonstrated that in all cases drug loaded PHEA-C16 and PHEA-PEG-C16 micelles provide a drug permeation across ocular epithelia greater than simple drug solutions or suspensions. In particular PHEA-PEG-C16 acts as the best permeability enhancer in our experimental model. In vivo bioavailability studies conducted with PHEA-PEG-C16 micelles loaded with dexamethasone alcohol, confirmed that this system also provides a drug bioavailability greater in comparison with that obtained with water suspension of the same drug after ocular administration to rabbits. [Copyright &y& Elsevier]

Abstract: Striated muscle tissue is an attractive target for gene delivery as it can be easily reached and can express exogenous proteins. However, administration of naked DNA results in low transfection levels, and the design and development of safe and efficient gene delivery systems are thus required. This review is focusing on the characteristics of the striated muscle tissue with regards to features possibly affecting gene transfer, as well as the different soluble polymers that have been evaluated as gene carriers. The described formulations are ranging from polymers displaying a high density of positive charges to non-ionic molecules. Nevertheless, polymers exhibiting few or no positive charges appear to our opinion as the most promising approach to achieve both safe and efficient transfection of the striated muscles. [Copyright &y& Elsevier]

The use of p,α-dimethylstyrene, potentially obtainable from renewable sources, as a substitute for styrene in the synthesis of amphiphilic copolymers is reported in this work. A series of novel poly(p,α-dimethylstyrene- co -maleic anhydride) (SMA) copolymers was synthesized, characterized, and studied as potential polymeric surfactants. After hydrolysis, the copolymers solution properties were compared to the similar and very well-known styrene-maleic acid copolymers. Both series of copolymers were synthesized using reversible addition-fragmentation chain transfer-mediated polymerization (RAFT), and a sample of poly(p,α-dimethylstyrene- co -maleic anhydride) was synthesized via classical free radical polymerization. The synthesized copolymers were studied from the point of view of their solution properties, with particular attention to the influence of the macromolecular and chemical structure on the surface tension of their aqueous solutions. Our results suggest that p,α-dimethylstyrene can be employed in copolymers with maleic anhydride, the resulting material being a valid alternative to SMA copolymers for various applications, such as emulsifiers and dispersants. Furthermore, the DMSMA series seems to be slightly more surface active than SMA. [Display omitted] • The use of a potentially biobased monomer to replace styrene in amphiphilic copolymers is proposed. • Amphiphilic copolymers with various molecular weights can be prepared by RAFT. • The prepared polymers do not form supramolecular aggregates in water. • Solution properties and toxicity are comparable to analogous styrene- co -maleic anhydride polymers. [ABSTRACT FROM AUTHOR]

Abstract: Amphiphilic copolymers containing β-cyclodextrin (β-CD) core were synthesized successfully. Synthesis was initiated from tosylated cyclodextrin ((Tosyl)7-β-CD) which is containing two types of functional groups. Hydroxyl functional groups of (Tosyl)7-β-CD were used as initiator for ring opening polymerization of lactide. This step led to star polymers containing tosylated cyclodextrin core and polylactide arms (PLA–(Tosyl)7-β-CD). In the next step, tosyl groups of PLA–(Tosyl)7-β-CD were used as initiator for ring opening polymerization of 2-ethyl-2-oxazoline and amphiphilic copolymers containing cyclodextrin core, PLA and poly(2-ethyl-2-oxazoline) arms (PLA–β-CD–POX) were obtained. Loading of Congo red as guest molecule by amphiphilic copolymers was investigated. The release of guest molecule from chloroform solution of copolymers to water phase was also investigated. [Copyright &y& Elsevier]

Abstract: Novel amphiphilic graft polyphosphazenes (PNIPAm/EtGly-PPPs) bearing poly (N-isopropylacrylamide) (PNIPAm) as a hydrophilic segment and ethyl glycinate (EtGly) as a hydrophobic group were synthesized via ring-opening polymerization and subsequent substitution reaction. The lower critical solution temperature (LCST) of copolymers was investigated by turbidity method using UV–Vis spectroscopy. Copolymers show their LCSTs in the range of 18.5–33°C, depending on the mole ratio of the substituents. The self-assembly characteristics of copolymers in aqueous solution was studied by using fluorescence technique, dynamic light scattering (DLS), and TEM. The critical association concentration (CAC) of copolymers varied from 0.112 to 0.0309g/L, was related with the mole ratio of PNIPAm to EtGly. The TEM images showed self-assembled nanoparticles with a spherical shape at about 30°C, while network-like aggregates were observed for copolymer with high PNIPAm content at relatively low temperature. The particle size of nanoparticles, depending on copolymer compositions, was in the range of 80–900nm at 25°C. These copolymers may be used as injectable drug carriers for the delivery of hydrophobic compounds. [Copyright &y& Elsevier]

Abstracts: New amorphous amphiphilic triblock copolymers of poly(3-hydroxybutyrate)–poly(ethylene glycol)–poly(3-hydroxybutyrate) (PHB–PEG–PHB) were synthesized using the ring-opening copolymerization of β-butyrolactone monomer. They were characterized by fluorescence, SEM and 1H NMR. These triblock copolymers can form biodegradable nanoparticles with core–shell structure in aqueous solution. Comparing to the poly(ethylene oxide)–PHB—poly(ethylene oxide) (PEO–PHB–PEO) copolymers, these nanoparticles exhibited much smaller critical micelle concentrations and better drug loading properties, which indicated that the nanoparticles were very suitable for delivery carriers of hydrophobic drugs. The drug release profile monitored by fluorescence showed that the release of pyrene from the PHB–PEG–PHB nanoparticles exhibited the second-order exponential decay behavior. The initial biodegradation rate of the PHB–PEG–PHB nanoparticles was related to the enzyme amount, the initial concentrations of nanoparticle dispersions and the PHB block length. The biodegraded products detected by 1H NMR contained 3HB monomer, dimer and minor trimer, which were safe to the body. [Copyright &y& Elsevier]

Abstract: Biodegradable polymers represent a class of extremely useful materials for many biomedical and pharmaceutical applications, as exemplified by drug delivery systems, which in recent years have taken advantage of (bio)degradable polymeric matrices. However, before being selected for any biomedical application, a biodegradable polymer requires careful investigation of its interactions and compatibility within the human body. To date, polyesters, both natural and synthetic, constitute the most fully developed class of degradable biomaterials. Poly(ε-caprolactone) (PCL) and polylactides (PLAs), recognized as biocompatible and biodegradable polyesters, are very promising for controlled drug delivery devices. Bacterial polyesters and malic acid-based polymers (poly(malic acid), PMLA and derivatives) are poly(β-hydroxyacid)-type polyesters that represent excellent alternatives for temporary therapeutic applications. Although these polyesters can be produced by polycondensation, high molecular weight structures have, until now, been produced almost exclusively by ring-opening polymerization (ROP) of the corresponding cyclic monomers. The ability of aluminum alkoxides (AlR x (OR′)3− x ) and tin(II) bis(2-ethylhexanoate) (Sn(Oct)2) to control the ROP of (di)lactones in terms of molecular parameters has opened the way to a wide range of molecular structures and topologies. Beyond the mechanistic and thermodynamic aspects of ROP of (di)lactones using organometallic compounds, this review is focused on new non-organometallic N-heterocyclic carbenes recently reported as catalysts for the controlled ROP of cyclic esters. Interestingly, the use of these simple organic molecules as catalysts or promoters in asymmetric polymer synthesis has provided organocatalytic alternatives to traditional organometallic reagents. [Copyright &y& Elsevier]

Abstract: Amphiphilic chitooligosaccharide-graft-poly(ε-caprolactone) (COS-g-PCL) copolymers were controllably synthesized using protection/deprotection technique of COS via trimethylsilyl groups and ring-opening polymerization of ε-caprolactone. Their crystalline properties were investigated with differential scanning calorimetry. With the increase of PCL content in graft copolymer, the values of ΔH and X c became enhanced, and T m shifted to higher temperatures. Micellar properties of amphiphilic graft copolymers were studied. Spherical micelles from COS11-g-PCL132 were prepared. However, due to the higher PCL content, the spherical micelles from COS11-g-PCL520 easily confused together so that the complicated network morphology was formed. Interestingly, hierarchical structure was observed in the formed network morphology, as being driven by the crystallization of PCL segments in micelles. Using pyrene as a model compound, the micelles from COS11-g-PCL132 copolymers can be loaded by hydrophobic therapeutic agent, potentially offering an appropriate vehicle for drug delivery. [Copyright &y& Elsevier]

Abstract: The new macroazoinitiators containing poly (propylene glycol), (PPG), with molecular weight 400 and 2000, having hydrophilic character, were synthesized and polymerized with styrene to prepare PS-b-PPG block copolymers. Cast films and e-spun films were prepared and contact angles of these films with water drop were measured to examine hydrophilic/hydrophobic behavior of the copolymers. Each e-spun film with average fiber diameters from 0.25 to 2.20μm was prepared in N,N-dimethylformamide (DMF) under controlled electrospinning process parameters such as polymer concentration, applied voltage and tip-to-collector distance. Scanning electron microscope (SEM) images of the electrospun films were taken to determine the fiber diameters. Surface compositions of the block copolymers were also determined by using an electron spectrometer with MgKα X-rays. NMR, and FT-IR spectroscopic, and GPC measurements were employed to characterize and determine the PPG contents (6–43%). From the results, electrospinning process increased the hydrophilic properties of the block copolymers obtained, compared their cast film forms. Our results suggest that these polymers are favorable in biological applications in cases where high ratio of the surface to volume and hydrophilicity are required simultaneously. Both chemical structure and topology of the films are important in wetting and hydrophobicity. [Copyright &y& Elsevier]

Abstract: Poly(ethylene oxide) monomethylether was functionalized by alkyl chains of various lengths (l=10–19 methylene groups) bearing a polymerizable methacrylate moiety. Each synthesis step on the polymer gives quantitative functionalization rates. The self-assembly of the amphiphilic polymers in water was studied by light scattering for various end-groups. Sterical and polar effects were shown to influence the micellization step. The cores of the micelles formed by PEO-Cl-methacrylate were irreversibly cross-linked by UV irradiation. Star polymers that are stable under dilution in good solvent are obtained after 1-min irradiation. The hydrodynamic radius and the molar mass of the nanoparticles depend on the amount of photoinitiator introduced in the cores. [Copyright &y& Elsevier]

Abstract: Our work focuses on the solubilization of tributylphosphate (TBP), a polar oil, in aqueous solutions of an L64 pluronic ((EO)13–(PO)30–(EO)13). The solubilization capacity of this amphiphilic copolymer highly depends on the temperature. Turbidity measurements show that the increase of the temperature provokes an increase of the hydrophobic character of L64 which favours the TBP solubilization capacity. Two significant temperatures are evidenced; the solubilization minimum temperature (SMT) and the cloud point temperature (CPT). The former is defined as the lowest temperature allowing TBP solubilization in the three-component system (L64–TBP–water). The latter is similar to the cloud point temperature (CPT) defined for the binary systems of water-amphiphile and depends on the copolymer structure, and, more interesting, is directly related to the TBP concentration in the medium. The dependence of CPT with TBP concentration is explained by the change in the hydrophobic character of the (PO)m block and thereby of the whole L64 molecule following solubilization of TBP. A [temperature–composition] diagram allows to delimit monophasic and diphasic domains and to define the optimal temperature for the maximal solubilization of TBP at a given L64 concentration. For a 10wt.% L64 solution, the temperature of 316K is required to solubilize a maximum quantity of TBP. Both turbidity and 1H NMR data suggest the occurrence of two different structures of the three-component system depending on the TBP concentration. During the addition of TBP, the solubilized aggregates turn from swelled aggregates or micelles of amphiphile to nanophase of TBP (nanoemulsion) stabilized by the L64, with an intermediate range of TBP concentration exhibiting a more complex gel-like or precipitated structure. Finally, the analysis of the 1H NMR chemical shifts give relevant information on the different interactions between TBP and L64 and thereby on the location of the TBP molecules in the aggregates. [Copyright &y& Elsevier]

Atom transfer radical polymerization (ATRP) catalyzed by N,N′,N′,N″,N″-pentamethyldiethylenetriamine (PMDETA)/CuBr was performed to synthesize poly (tert-butyl acrylate) (PtBA-Br) with predesigned molecular weight and narrow polydispersity. Using the PtBA-Br as macroinitiator, the PtBA-block-PS copolymer was prepared through ATRP. After terminated bromine atom was converted to end-functional azide group (P(tBA-b-St)-N3), C60 end-capped PtBA-PS block copolymers (P(tBA-b-St)-C60) were synthesized by reacting C60 with P(tBA-b-St)-N3. GPC characterizations showed that C60 was chemically bonded to the end of P(tBA-b-St) chain and the products were mono-substituted. FT-IR, UV-Vis measurements confirmed that hydrolysis of P(tBA-b-St)-C60 resulted in amphiphilic C60 end-capped PAA-PS block copolymers. In additional, the photoconductivity of P(tBA-b-St)-C60 was measured. [Copyright &y& Elsevier]

Well-defined amphiphilic block copolymers polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) and polystyrene-b-polyethylene oxide (PS-b-PEO) with controlled block length were synthesized using atomic-transfer radical polymerization (ATRP). The films fabricated by drop coating the block copolymer solution on mica show the marked microphase separated morphologies, which strongly depend on the block length ratio. The furrow maps of these films predict that they can be used as templates to prepare inorganic nanoparticles. [Copyright &y& Elsevier]

Oil-in-water nanoemulsions were prepared using a series of synthetic graft copolymers with a backbone of dextran (DEX) and a number of side chains of poly-&epsiv;-caprolactone (PCL). In this paper, we focus on the o/w emulsion stabilizing abilities of these novel PCL-DEX copolymers, using a recently developed optical analyzer (Turbiscan). The main advantage of Turbiscan is to detect the destabilization phenomena in non-diluted emulsion, much earlier than the naked eye’s operator, especially in the case of an opaque and concentrated system. This study shows that PCL-DEX copolymers successfully stabilized ethyl acetate-in-water emulsions, even in the absence of additional surfactants, whereas they were not efficient in stabilizing methylene chloride-in-water emulsions which coalesced fast and irreversibly. The ethyl acetate-in-water emulsion stabilizing ability of PCL-DEX seemed to be related to the localization of their blocks with regard to the oil–water interface. [Copyright &y& Elsevier]