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Natural single‐chain nanoparticles (SCNPs) such as proteins have inspired research into the formation and application of synthetic SCNPs. Although the latter can mimic general aspects of the self‐assembly behavior of their biological counterparts, these systems remain relatively understudied. In this respect, a systematic series of amphiphilic statistical copolymers (ASC) of different molecular weights, with a hydrophilic comonomer (methacrylic acid) and varying hydrophobic comonomer to encompass methacrylates of different hydrophobicity, are synthesized. Small‐angle X‐ray scattering studies confirmed that SCNPs are achieved for each copolymer series when dispersed in basified water at 1% w/w. When the aggregation number of the ASC nanoparticles is close to unity the particle shape elongates resulting in a larger particle surface area to volume ratio, allowing more hydrophilic groups to locate on the particle surface tending to keep the particle surface charge density (PSC) constant. Thus, within a series, particle elongation increases with copolymer molecular weight. Structural parameters of SCNPs formed by ASCs composed of hydrophobic components with low partition coefficients are well consistent with predictions obtained from the PSC model. These results highlight the main parameters, namely molecular weight and acid content, responsible for the SCNP formation and provide insight into how specific particle morphology can be targeted. [ABSTRACT FROM AUTHOR]

This manuscript presents the synthesis of hyperbranched amphiphilic poly (lauryl methacrylate-co-tert-butyl methacrylate-co-methacrylic acid), H-P(LMA-co-tBMA-co-MAA) copolymers via reversible addition fragmentation chain transfer (RAFT) copolymerization of tBMA and LMA, and their post-polymerization modification to anionic amphiphilic polyelectrolytes. The focus is on investigating whether the combination of the hydrophobic characters of LMA and tBMA segments, as well as the polyelectrolyte and hydrophilic properties of MAA segments, both distributed within a unique hyperbranched polymer chain topology, would result in intriguing, branched copolymers with the potential to be applied in nanomedicine. Therefore, we studied the self-assembly behavior of these copolymers in aqueous media, as well as their ability to form complexes with cationic proteins, namely lysozyme (LYZ) and polymyxin (PMX). Various physicochemical characterization techniques, including size exclusion chromatography (SEC) and proton nuclear magnetic resonance (1H-NMR), verified the molecular characteristics of these well-defined copolymers, whereas light scattering and fluorescence spectroscopy techniques revealed promising nanoparticle (NP) self- and co-assembly properties of the copolymers in aqueous media. [ABSTRACT FROM AUTHOR]

In this study, reversible addition-fragmentation chain transfer (RAFT) polymerization is utilized in order to synthesize novel hyperbranched poly(oligoethylene glycol) methyl ether methacrylate-co-tert-butyl methacrylate-co-methacrylic acid) (H-[P(OEGMA-co-tBMA-co-MAA)]) copolymers in combination with selective hydrolysis reactions. The copolymers showing amphiphilicity induced by the polar OEGMA and hydrophobic tBMA monomeric units, and polyelectrolyte character due to MAA units, combined with unique macromolecular architecture were characterized by physicochemical techniques, such as size exclusion chromatography (SEC) and 1H-NMR spectroscopy. The hyperbranched copolymers were investigated in terms of their ability to self-assemble into nanostructures when dissolved in aqueous media. Dynamic light scattering and fluorescence spectroscopy revealed multimolecular aggregates of nanoscale dimensions with low critical aggregation concentration, the size and mass of which depend on copolymer composition and solution conditions, whereas zeta potential measurements indicated pH sensitive features. In addition, aiming to evaluate their potential use as nanocarriers, the copolymers were studied in terms of their drug encapsulation and protein complexation ability utilizing curcumin and lysozyme, as a model hydrophobic drug and a model cationic protein, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Symmetric 14-armed βCD-cored star amphiphilic block copolymers βCD-(PBO-PGL) 14 were obtained with tunable arm block lengths, high purity and low polydispersity. • Star copolymers βCD-(PBO-PGL) 14 have similar self-assembly behavior compared to linear analogues (PGL-PBO-PGL). • Polymersomes made from βCD-(PBO-PGL) 14 have different ion permeability behavior compared to linear analogues (PGL-PBO-PGL). For polymersome-based nanoreactor purposes, we herein present the synthesis and characterization of well-defined star amphiphilic copolymers composed of a beta -cyclodextrin (βCD) core and seven poly(butylene oxide)- block -polyglycidol (PBO-PGL) arms per side (βCD-(PBO-PGL) 14). The self-assembly behavior of 14-armed βCD-(PBO-PGL) 14 and PGL-PBO-PGL (linear analogues without the βCD segment) was investigated using scattering techniques for comparison. The morphologies, including vesicles and micelles, are governed by the hydrophobic-to-hydrophilic (weight) ratio, regardless of the polymer architecture (linear or star). Interestingly, despite notable differences in polymer conformation, the produced supramolecular structures were evidenced to be fairly similar on the structural point of view. We subsequently investigated the ion permeability of the membranes of the self-assemblies focusing on the impact of the presence of βCD. The results demonstrated that the βCD-containing vesicular membranes are less permeable to H+, compared with βCD-free vesicular membranes. The presence of βCD in planar membranes also influences the K+Cl− permeability to some extent. Thus, βCD-containing membranes can be considered as potential candidates in designing nano-containers towards applications where precise changes in environmental pH are required. [ABSTRACT FROM AUTHOR]

By combining oppositely charged polydiallyldimethylammonium chloride (PDADMAC) and sodium polyacrylate (NaPA), interpolyelectrolyte complexes (IPECs) can be formed in aqueous solution. Such IPECs are studied for rather short NaPA and under variation of the Mw of PDADMAC. The focus is on elucidating the effect of having a hydrophobic modification of the NaPA, which is introduced by having 10 mol% of the monomeric units substituted by ones carrying a dodecyl alkyl chain. This modification renders the complexes more hydrophobic, which is seen in the fact that precipitation of the complexes occurs at a lower mixing ratio and the biphasic region is also wider. The structures of the soluble IPECs are studied by a combination of light and neutron scattering (SANS). It is observed that the complexes formed possess typical radii of gyration of ≈30–40 nm, which become somewhat smaller with increasing length of the PDADMAC chain. The SANS data can be described well with the Beaucage model for complexes, where locally small hydrophobic domains of cylindrical shape are formed, whose persistence length decreases with increasing content of NaPA in the complexes. In contrast no such structures are seen for NaPA without the hydrophobic modification. The cylindrical domains are then arranged within larger‐sized clusters of 30–40 nm, which become more compact with reduced length of the PDAMAC chains. The structure of the IPECs is largely determined by the presence of the hydrophobic modification of the NaPA and is further controlled by the length of the hydrophobic modification. Such IPECs of controlled structure, relatively small size, and containing hydrophobic domains are potentially interesting as delivery systems due to having domains of variable polarity. [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]

We report the synthesis and the micellar self‐assembly in aqueous media of novel amphiphilic block copolymers. The copolymers consist of a poly[(methyl methacrylate)‐co‐(hydroxypropyl methacrylate)] statistical copolymer block and a poly[oligo(ethylene glycol) methyl ether methacrylate] block, and were synthesized by reversible addition–fragmentation chain transfer polymerization. The amphiphilic P(MMA‐co‐HPMA)‐b‐POEGMA block copolymers contain monomers of differing polarity and in varying ratios. Furthermore, HPMA segments are chosen in order to enhance hydrogen bonding interactions within the core of spherical micelles formed by the copolymers in aqueous media, as evidenced by light scattering and fluorescence spectroscopy studies. The amphiphilic copolymers are able to encapsulate the hydrophobic drugs curcumin and indomethacin as found using light scattering and spectroscopic methods. © 2021 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

The formation of monolayers of poly(fluoro(meth)acrylate)-b-poly(acrylic acid) (PFA-b-PAA) amphiphilic diblock copolymers at the air/water interface was characterized with the Langmuir film balance technique and atomic force microscopy. Both internal and external effects on the aggregation behaviour of the amphiphilic copolymers were considered. The structure of fluorinated hydrophobic part, as an internal factor, affects the surface behaviour of the amphiphilic copolymers through changes in the packing density of the hydrophobic core. The morphology of the LB films of all the three copolymers exhibit circular micelles with the hydrophobic core and hydrophilic coronas. The variation in pH and ionic strength leads to changes in charge distribution of PAA coronas. The surface area occupied by the PFA-b-PAA copolymers decrease with the rise of pH of subphase. The increase in salt concentration provides for the reduction of electrostatic repulsion between the hydrophilic blocks. [ABSTRACT FROM AUTHOR]

Amphiphilic copolymers with poly (alkyl acrylate) as hydrophobic and poly (acrylic acid) (AA) as hydrophilic block have been synthesised. The alkyl chain was varied from butyl to dodecyl, thereby varying systematically the polarity of the hydrophobic block whose length was between 35 and 70, while the PAA block had ~ 100 units. Such relatively short amphiphiles should equilibrate quickly in aqueous solution, and their corresponding self-assembly properties were characterised by means of critical micelle concentration (cmc) determination. Detailed information regarding the aggregate structures was obtained by static light scattering (SLS) and small angle neutron scattering (SANS). This could be correlated with the molecular architecture of the copolymers and the degree of ionisation of the PAA block. Generally, it is found that the aggregation numbers become smaller upon fully charging the PAA head group and only for dodecyl acrylate really well-defined micellar aggregates are formed. This means that the extent of hydrophobicity of the alkyl acrylate block and its length determine in a clear fashion the propensity for micelle formation and the mass and aggregation number of the formed micelles. [ABSTRACT FROM AUTHOR]

ABA and BAB triblock amphiphilic copolymers based on sucrose methacrylate and methyl methacrylate are synthesized by sequential reversible addition–fragmentation chain transfer polymerization using S,S′‐bis(R,R′‐dimethyl‐R′′‐acetic acid)‐trithiocarbonate as a chain transfer agent. The copolymers present narrow molar mass dispersity, controlled molar mass and architecture as determined by gel permeation chromatography and 1H and 13C nuclear magnetic resonance. The copolymers with molar and mass fractions of poly(sucrose methacrylate) block ranging from 1 to 22 mol% and 3 to 52 wt%, respectively, and different molar masses present characteristics of a surfactant such as self‐assembly. The self‐assembly of the triblock copolymers in water, N,N‐dimethylformamide (DMF), dichloromethane, tetrahydrofuran, or benzene results mostly in vesicles as confirmed by scanning electron microscopy images and small‐angle X‐ray of the dispersions. Moreover, the copolymers present the capability to stabilize aromatic molecules (Nile Red dye) and nonpolar solvents in an aqueous phase and polar ionic molecules (methylene blue) and water in a nonpolar medium, suggesting the potential for application in drug encapsulation, environmental remediation systems, and molecular extraction in liquid–liquid immiscible systems, for example. Films prepared by casting from copolymer solutions in DMF present a lamellar structure with the lamellar thickness varying according to the copolymer molar mass. [ABSTRACT FROM AUTHOR]

Conformity of two biological imaging entities, magnetic resonance imaging (MRI) and fluorescence imaging, is achieved through co‐assembly of a Gd(III)‐based metallosurfactant, conjugated polymeric nanoparticles, and amphiphilic block copolymer F127 (PEO106PPO70PEO106) followed by crosslinking with organosilica. The cross‐linked micelles with a size around 100 nm exhibit outstanding dispersion stability in aqueous and phosphate buffered saline solutions, bright fluorescence emission, and high relaxivities, providing a new approach to synthesize highly efficient bimodal contrast agents. The relaxivities of the co‐assembled micelles are synergistically enhanced by incorporation of Gd(III) complexes with high hydration number (q = 3) and elongation of rotation correlation time to achieve r1 values up to 105.37 mm−1 s−1 (at 1.5 T), which is over 20 times that of clinically used MRI contrast agents and among the highest values of all the nanoparticular MRI contrast agents. The external PEO layer endows these micelles with very low cytotoxicity for both in vitro and in vivo imaging. Meanwhile, thanks to the enhanced permeability and retention effect originating from their nanoscale sizes, the bimodal contrast agents show a prolonged blood circulation time in vivo and targeted accumulation at tumor regions to display outstanding MRI imaging performance. [ABSTRACT FROM AUTHOR]

A novel method was presented to create composite micelles of amphiphilic copolymers and Ag nanoparticles (NPs) in a three-dimensional co-flow focusing microfluidic device (3D CFMD). Self-assembly of the copolymers was initiated by the fast mixing of water and a blend dispersion of hydrophobic Ag NPs and amphiphilic copolymers. At the same time, the hydrophobic Ag NPs enter the core of copolymer micelles, based on the hydrophobic interaction. The copolymer-Ag NPs composite micelles have a core-shell structure with copolymer shell and Ag NPs core. COMSOL Multiphysics is used to simulate the concentration distribution of copolymers and Ag NPs under different flow rates. Co-assembly microfluidic conditions are determined based on simulation results. Under suitable microfluidic conditions, both block copolymers and gradient copolymers can co-assemble with hydrophobic Ag NPs to form composite micelles, respectively. This microfluidic coassembly method will have a good prospect in the preparation of composite micelles of amphiphilic copolymers and metal nanoparticles. [ABSTRACT FROM AUTHOR]

Liquid-liquid phase separation (LLPS) can provide micron-sized liquid compartments dispersed in an aqueous medium. This phenomenon is increasingly appreciated in natural systems, e.g. , in the formation of intracellular membraneless organelles, as well as in synthetic counterparts, such as complex coacervates and vesicles. However, the stability of these synthetic phase-separated microstructures versus coalescence is generally challenged by the presence of salts and/or surfactants, which narrows the range of possible applications. We propose a new strategy to obtain micron-sized liquid domains via LLPS, by mixing an amphiphilic copolymer with surfactants and sodium citrate in water at room temperature. Combining Confocal Laser Scanning Microscopy (CLSM) and Differential Scanning Calorimetry (DSC) with Dissipative Particle Dynamics (DPD) simulations, we map the phase diagram to detect LLPS and address the presence and morphology of these microscopic domains. This mapping in turn provides a first mechanistic hypothesis for the formation of such confined polymer-rich microenvironments. LLPS is driven by the phase behavior of the copolymer in water and by its associative interactions with surfactants, combined with the water-sequestering ability of salting-out electrolytes. The key factor for LLPS and formation of microdomains is the entropy-driven dehydration of the copolymer head groups, which can be quantified through the Free Water Content (FWC). Interestingly, the internal morphology of the LLPS microdomains is finely controlled by the ratio between nonionic and anionic surfactants. Beside its applicative potential, this approach represents a tool for designing synthetic mimics that improve our understanding of the occurrence of LLPS in cells. [ABSTRACT FROM AUTHOR]

Aliphatic polycarbonate-based block copolymers have received considerable attention as carriers for targeted drug and gene delivery because of their biocompatibility and biodegradability. However, there is little understanding of their phase behaviour and physicochemical characterization of the particles made from them. Here, we prepared a series of well-defined poly(trimethylene carbonate) (PTMC)-based copolymers with molar masses of 3-9 kg·mol-1 by metal-free ring-opening polymerization using dihydroxy-terminated poly(ethylene oxide) as a macroinitiator. Micellar nanoparticles self-assembled from copolymers had a size of less than 130 nm. They were degraded by the action of a model lipase from Mucor Miehei at 37 °C, which is of high importance for biodegradability in the living organism. X-ray diffraction and differential scanning calorimetry proved that amorphous copolymers with more than 39 mol% of carbonate units and representative particles were prone to the rearrangement of PTMC chains during storage and to thus undergo post-crystallization. Our findings can contribute to the comprehensive characterization of polycarbonate biomaterials for medical applications. [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]

Poly (diethyl vinylphosphonate-co-2-chloroethyl methacrylate) (P(DEVP-co-CEMA)) copolymers are synthesized by free radical copolymerization initiated by benzoyl peroxide. The reactivity ratios for the free radical copolymerization of CEMA (M1) and DEVP (M2) arer1 = 19.45 andr2 = 0.11, respectively. The desired amphiphilic copolymers with relatively low polydispersity index (PDI) and different DEVP contents are isolated and purified from the reaction mixtures through precipitation fractionation. The structures and molecular characteristics of the obtained products are characterized by1H NMR, FTIR, and SEC analysis. All of these fractionated copolymers have a unimodal distribution and moderate PDI. The thermal properties of the P(DEVP-co-CEMA) copolymers are investigated by TGA and differential scanning calorimetry (DSC) measurements. Single glass transition temperature (Tg) appears in the DSC profiles differing from the existence of twoTgs in the blend of poly (diethyl vinylphosphonate) and poly (2-chloroethyl methacrylate), which indicates the random structure of the copolymers. The MALDI–ToF mass analysis further reveals that DEVP and CEMA units are randomly distributed in the copolymer chains. The self-assembly behavior of the P(DEVP-co-CEMA) copolymers in aqueous solution is preliminarily investigated. [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 Copper-catalyzed azide-alkyne cycloaddition (CuAAC) was used to prepare glycosylated polyethylene (PE)-poly(ethylene glycol) (PEG) amphiphilic block copolymers. The synthetic approach involves preparation of alkyne-terminated PE- b-PEG followed by CuAAC reaction with different azide functionalized sugars. The alkyne-terminated PE- b-PEG was prepared by etherification reaction between hydroxyl-terminated PE- b-PEG ( Mn ∼ 875 g mol−1) and propargyl bromide and azidoethyl glycosides were prepared by glycosylation of 2-azidoethanol. Atmospheric pressure solids analysis probe-mass spectrometry was used as a novel solid state characterization tool to determine the outcome of the CuAAC click reaction and end-capping of PE- b-PEG by the azidoethyl glycoside group. The aqueous solution self-assembly behavior of these amphiphilic glycosylated polymers was explored by TEM and dye solubilization studies. Carbohydrate-bearing spherical aggregates with the ability to solubilize a hydrophobic dye were observed. The potential of these amphiphilic glycosylated polymers to self-assemble via electro-formation into giant carbohydrate-bearing polymersomes was also investigated using confocal fluorescence microscopy. An initial bioactivity study of the carbohydrate-bearing aggregates is furthermore presented. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5184-5193 [ABSTRACT FROM AUTHOR]

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: A new type of copolymer containing two alternating segments, poly-(styrene-alt-maleic anhydride)-co-poly (7-(4-vinylbenzyloxyl)-4-methylcoumarin-alt-maleic anhydride) P(St-alt-MAn)-co-P(VM-alt-MAn)(PSMVM), was prepared. The copolymer self-assembled into nanoparticles with internal microphase structures in water because the hydrophilicity of segment P(VM-alt-MAn) is higher than that of P(St-alt-MAn). The particle size, morphology, ζ potential and surface properties and their dependence on the pH and slat concentrations were studied with a combination of techniques. The nanoparticles of PSMVM showed surface activity and pH sensitivity for producing Pickering oil-in-water emulsions. The emulsion volume increased and the size of oil/water droplet decreased with increasing salt concentration. Furthermore, cross-linked nanoparticles (CLPs) were obtained by photo-dimerization of the pendent coumarin groups in PSMVM under UV irradiation. The emulsions produced by using the CLPs as emulsifiers showed even better stability upon standing. Solid oil-phase droplets were obtained by preparation of CLPs-stabilized Pickering emulsions with an oil phase of styrene containing the initiator AIBN followed by the polymerization of styrene. Thus, the enrichment and aggregation of the CLPs on the emulsion droplets was visible because the solid droplets remained unchanged during the SEM sample preparation. [ABSTRACT FROM AUTHOR]

Two chiral amphiphilic diblock copolymers with different relative lengths of the hydrophobic and hydrophilic blocks, poly(6‐O‐p‐vinylbenzyl‐1,2:3,4‐Di‐O‐isopropylidene‐D‐galactopyranose)‐b‐poly(N‐isopropylacrylamide) or poly(VBCPG)‐b‐poly(NIPAAM) and poly(20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one methacrylate)‐b‐poly(N‐isopropylacrylamide) or poly(MAC‐HPD)‐b‐poly(NIPAAM) were synthesized via consecutive reversible addition‐fragmentation chain‐transfer polymerizations of VBCPG or MAC‐HPD and NIPAAM. The chemical structures of these diblock copolymers were characterized by 1H nuclear magnetic resonance spectroscopy. These amphiphilic diblock copolymers could self‐assemble into micelles in aqueous solution, and the morphologies of micelles were investigated by transmission electron microscopy. By comparison with the lower critical solution temperatures (LCST) of poly(NIPAAM) homopolymer in deionized water (32 °C), a higher LCST of the chiral amphiphilic diblock copolymer (poly(VBCPG)‐b‐poly(NIPAAM)) was observed and the LCST increased with the relative length of the poly(VBCPG) block in the copolymer from 35 to 47 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7690–7701, 2008 [ABSTRACT FROM AUTHOR]

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]

Four‐arm star‐shaped poly[2‐(diethylamino)ethyl methacrylate]‐b‐poly[2‐hydroxyethyl methacrylate]s block copolymers using tetraphenylsilane (TPS) as a core with adjustable arm lengths are synthesized through two‐step atom transfer radical polymerizations. For comparison, a linear block copolymer with similar molecular weight is also prepared. The assembled star‐shaped copolymer micelles exhibit sizes of 102–139 nm and critical micelle concentrations of 1.49–3.93 mg L−1. Moreover, the bulky and rigid TPS core is advantageous for propping up the four star‐shaped arms to generate large intersegmental space. As a result, the drug‐loading capacity in the micelles is up to 33.97 wt%, much surpassing the linear counterpart (8.92 wt%) and the previously reported star‐shaped copolymers prepared using pentaerythritol as the core. Furthermore, the micelles show sensitive pH‐responsive drug release when the pH changes from 7.4 to 5.0. The in vitro cytotoxicity to Hela cells indicates that the doxorubicin (DOX)‐loaded micelles have similar anticancer activity to the pristine DOX. The combination of excellent micelle stability, high drug‐loading, sensitive pH response, and good anticancer activity endows the copolymers with promising application in drug control delivery for anticancer therapy. [ABSTRACT FROM AUTHOR]