Versatile Synthesis of Multiarm and Miktoarm Star Polymers with a Branched Core by Combination of Menschutkin Reaction and Controlled Polymerization

The Structure-Self-Assembly Relationship in PDMAEMA/Polyester Miktoarm Stars

Well-defined miktoarm star-shaped polymers based on heterofunctional glucose derivative initiator, N,N’-dimethylaminoethyl methacrylate (DMAEMA) and various cyclic esters, such as ε-caprolactone (CL), lactide (LA), glycolide (GA), were obtained by combining atom...

Rational design of a multi-in-one heterofunctional agent for versatile topological transformation of multisite multisegmented polystyrenes

A “seven-in-one” initiating, coupling and stimuli-labile agent is designed to achieve topological transformations with reduced, similar and enhanced molar masses.

Star amphiphilic block copolymers: synthesis via polymerization-induced self-assembly and crosslinking within nanoparticles, and solution and interfacial properties

The star amphiphilic block copolymer of star s-PNIPAM-b-PS is synthesized and it shows characteristics significantly different from those of the linear block copolymer counterpart.

One-Pot Synthesis of Dual-Responsive Hyperbranched Polymeric Prodrugs Using an All-in-One Chain Transfer Monomer

Over the past decades, tremendous progress has been advanced in the preparation of hyperbranched polymers (HPs), especially for the one-pot synthesis of segmented HPs by using self-condensing vinyl polymerization based on controlled living radical polymerization techniques. However, the fabrication of hyperbranched polymeric prodrugs (HPPs) still requires multistep postpolymerization conjugations, which generally suffer from low and uncontrolled conjugation efficacy of drug molecules due to the steric hindrance, low yields because of multistep synthesis, and scale-up difficulties attributed to batch-to-batch variations. To further address these issues and provide a highly straightforward and robust strategy toward HPPs, we reported in this study the one-pot preparation of dual-responsive hyperbranched polymeric prodrugs (DRHPPs) using an all-in-one chain transfer monomer that integrates a drug molecule with both acidic pH- and reduction-sensitive links. The resulting DRHPPs with precisely regulated drug loading content and great therapeutic efficacy offered a highly promising platform for efficient anticancer drug delivery.

Star-Shaped Thermoresponsive Polymers with Various Functional Groups for Cell Sheet Engineering

This study demonstrates the facile preparation of poly(N-isopropylacrylamide) (PNIPAM)-immobilized Petri dishes by drop-casting a star-shaped copolymer of hyperbranched polystyrene (HBPS) possessing PNIPAM arms (HBPS-g-PNIPAM) functionalized with polar groups. HBPS was synthesized via reversible addition-fragmentation chain transfer (RAFT) self-condensing vinyl polymerization (SCVP), and HBPS polymers with different terminal structures were prepared by changing the monomer structure. HBPS-g-PNIPAM was synthesized by the grafting of PNIPAM from each terminal of HBPS. To tune the cell adhesion and detachment properties, polar functional groups such as carboxylic acid and dimethylamino groups were introduced to HBPS-g-PNIPAM. Based on surface characterization using scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements, the advantage of the hyperbranched structure for the PNIPAM immobilization was evident in terms of the uniformity, stability, and thermoresponsiveness. Successful cell sheet harvesting was demonstrated on dishes coated with HBPS-g-PNIPAM. In addition, the cell adhesion and detachment properties could be tuned by the introduction of polar functional groups.

Radiant star nanoparticle prodrugs for the treatment of intracellular alveolar infections

Radiant star nanoparticle prodrugs were synthesized in a two-step process by first homopolymerizing RAFT transmers followed by copolymerization from the hyperbranched polymer core.

Synthesis and self-assembly of a dual-responsive monocleavable ABCD star quaterpolymer

A modularly synthesized core-functionalized PEG-PSt-PCL-PAA miktoarm star can self-assemble into hollow nanocapsules that are sensitive to pH/redox stimuli and H-bond/polyion complexation.

Relationships between Architectures and Properties of Highly Branched Polymers: The Cases of Amorphous Poly(trimethylene carbonate) and Crystalline Poly(ε-caprolactone)

Highly branched polymers (HBPs) are a special class of functional polymeric materials and possess unique properties due to their unique topological structure. A new series of highly branched linear-comb and star-comb amorphous poly(trimethylene carbonate)s (PTMC) and crystalline poly(ε-caprolactone)s (PCL) with well-defined structure and high molecular weight were first synthesized using hydroxylated polybutadiene (HPB) as macroinitiators by simple "one-step" and "graft from" strategies. It is expected that the impact of long-chain, highly branched architecture on the properties of amorphous and crystalline polymers, respectively, is different. We explored systematically for the first time the effect and comparison of branched architectures on the physical and chemical properties of highly branched PTMCs and PCLs, including the intrinsic viscosity, glass transition, thermal degradation, creep property, rheological property, and crystallization and melting behaviors. It is found that the intrinsic viscosities in solution for both comb-branched PTMCs and PCLs were much lower compared with their linear and star counterparts arise from more compact structure and smaller hydrodynamic volumes. For amorphous PTMC, the creep strain and rate increased remarkably with degree of branching increasing due to the shorter side chains making it difficult for the highly branched molecules to entangle. For crystalline PCL, both WAXD and DSC analysis of PCLs with different topological structures indicated that the comb branched architectures have no significant influence on the crystal structure of PCL, but greatly promote the crystallization behavior, e.g., higher crystallinities. The deep understanding of structure-property relationship expects to guide the synthesis of designed functional polymer materials and the processing of polymer products.

Hyperbranched polymers via RAFT self-condensing vinyl polymerization

RAFT-mediated self-condensing vinyl polymerization is a promising synthetic tool to create well-defined hyperbranched polymers.

Modular segmented hyperbranched copolymers

Modular segmented hyperbranched polymers, amenable to facile post-polymerization functionalization, were created via two distinct approaches.

Facile synthesis of photolabile dendritic-unit-bridged hyperbranched graft copolymers for stimuli-triggered topological transition and controlled release of Nile red

Successive RAFT SCVP and ROP were used to generate novel hyperbranched graft copolymers with the ability for the photo-triggered degradation and accelerative release of hydrophobic dye.

Synthesis, postmodification and fluorescence properties of reduction-cleavable core-couplable miktoarm stars with a branched core

Postmodification of (PEG)_m(PCL)_n miktoarm stars with a dual-reactive branched core allowed the introduction of versatile functionalities, and the coumarin-functionalized star exhibited tunable fluorescence properties sensitive to solvent polarity and reduction stimulus.

PNIPAM-based heteroarm star-graft quarterpolymers: synthesis, characterization and pH-dependent thermoresponsiveness in aqueous media

We report the design of PS_n(P2VP-b-PAA-g-PNIPAM)_n heteroarm star-graft quarterpolymers, the thermoresponsiveness of which is strongly dependent on pH ionic strength, and their macromolecular features, e.g. arm number and grafting density.

Facile synthesis of silica nanoparticles grafted with quaternized linear, comblike and toothbrushlike copolymers

The alkoxysilane–hydroxyl coupling reaction, quaternization and RAFT polymerization were combined to synthesize three types of quaternized copolymers grafted silica with thermo-dependent surface wettability.

Cell-penetrating hyperbranched polyprodrug amphiphiles for synergistic reductive milieu-triggered drug release and enhanced magnetic resonance signals

The rational design of theranostic nanoparticles exhibiting synergistic turn-on of therapeutic potency and enhanced diagnostic imaging in response to tumor milieu is critical for efficient personalized cancer chemotherapy. We herein fabricate self-reporting theranostic drug nanocarriers based on hyperbranched polyprodrug amphiphiles (hPAs) consisting of hyperbranched cores conjugated with reduction-activatable camptothecin prodrugs and magnetic resonance (MR) imaging contrast agent (Gd complex), and hydrophilic coronas functionalized with guanidine residues. Upon cellular internalization, reductive milieu-actuated release of anticancer drug in the active form, activation of therapeutic efficacy (>70-fold enhancement in cytotoxicity), and turn-on of MR imaging (∼9.6-fold increase in T1 relaxivity) were simultaneously achieved in the simulated cytosol milieu. In addition, guanidine-decorated hPAs exhibited extended blood circulation with a half-life up to ∼9.8 h and excellent tumor cell penetration potency. The hyperbranched chain topology thus provides a novel theranostic polyprodrug platform for synergistic imaging/chemotherapy and enhanced tumor uptake.

Self-assembly of amphiphilic hyperbranched poly (aryl ether ketone)-block-poly (ethylene glycol) copolymer into microspheres with excellent thermal property

An amphiphilic hyperbranched rod-coil copolymer was synthesized by grafting linear poly (ethylene glycol) (PEG) onto hydroxyl-terminated hyperbranched poly (aryl ether ketone) (OH-HPAEK). The molecular structure, the number-average molecular weight and the thermal properties of HPAEK- block-PEG were confirmed and characterized using proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, gel permeation chromatography, differential scanning calorimetry, and thermogravimetric analysis, respectively. The microspheres of HPAEK- block-PEG were fabricated by the method of self-assembly, and the morphology and diameter of the obtained microspheres were characterized using transmission electron microscopy, scanning electron microscopy, and dynamic light scattering. The heat-treated experimental results demonstrated that the polymer microspheres possessed excellent thermal property that could stably exist even if heated at 130°C for 10 h. In addition, the diameter of the microspheres can be easily controlled by just adjusting the concentration of the copolymer.

Synthesis and properties of heterografted toothbrush-like copolymers with alternating PEG and PCL grafts and tunable RAFT-generated segments

Novel (A-g-D)(B-alt-C)_mD-type heterografted toothbrush-like copolymers with great potential in smart drug delivery systems and thermo-responsive surface materials are investigated.