https://spectrum.library.concordia.ca/973679/1/DJS-JKO-KM_-_PPS_2011_-_ATRP_Bio_review_Revision_fnal.pdf

ATRP in the design of functional materials for biomedical applications

Polylactide (PLA) and its copolymers are one type of hydrophobic aliphatic polyester based on hydroxyalkanoic acids. They possess exceptional qualities: biocompatibility; FDA approval for clinical use; biodegradability by enzyme and hydrolysis under physiological conditions; low immunogenicity; and good mechanical properties. These critical properties have facilitated their value as sutures, implants for bone fixation, drug delivery vehicles, and tissue engineering scaffolds in pharmaceutical and biomedical applications. However, the hydrophobicity of PLA and its copolymers remains concerns for further biological and biomedical applications. One promising approach is to design and synthesize well-controlled PLA-based amphiphilic block copolymers (ABPs); typical hydrophilic copolymers include poly(meth)acrylates, poly(ethylene glycol), polypeptides, polysaccharides, and polyurethanes. This review summarizes recent advances in the synthesis and self-assembly of PLA-containing ABPs and their bio-related applications including drug delivery and imaging platforms of self-assembled nanoparticles, and tissue engineering of crosslinked hydrogels.

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Polylactide (PLA)-based amphiphilic block copolymers: synthesis, self-assembly, and biomedical applications

Multifunctional triblock copolymers for intracellular messenger RNA delivery

Towards the development of polycaprolactone based amphiphilic block copolymers: molecular design, self-assembly and biomedical applications.

Polymer vectors via controlled/living radical polymerization for gene delivery

A series of well-defined amphiphilic triblock copolymers [polyethylene glycol monomethyl ether]-block-poly(e-caprolactone)-block-poly[2-(dimethylamino)ethyl methacrylate] (mPEG-b-PCL-b-PDMAEMA or abbreviated as mPEG-b-PCL-b-PDMA) were prepared by a combination of ring-opening polymerization and atom transfer radical polymerization. The chemical structures and compositions of these copolymers have been characterized by Fourier transform infrared spectroscopy, 1H NMR, and thermogravimetric analysis. The molecular weights of the triblock copolymers were obtained by calculating from 1H NMR spectra and gel permeation chromatography measurements. Subsequently, the self-assembly behavior of these copolymers was investigated by fluorescence probe method and transmission electron microscopy, which indicated that these amphiphilic triblock copolymers possess distinct pH-dependent critical aggregation concentrations and can self-assemble into micelles or vesicles in PBS buffer solution, depending on the length of PDMA in the copolymer. Agarose gel retardation assays demonstrated that these cationic nanoparticles can effectively condense plasmid DNA. Cell toxicity tests indicated that these triblock copolymers displayed lower cytotoxicity than that of branched polyethylenimine with molecular weight of 25 kDa. In addition, in vitro release of Naproxen from these nanoparticles in pH buffer solutions was conducted, demonstrating that higher PCL content would result in the higher drug loading content and lower release rate. These biodegradable and biocompatible cationic copolymers have potential applications in drug and gene delivery. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1079–1091, 2010

Biocompatible and pH-responsive triblock copolymer mPEG-b-PCL-b-PDMAEMA: Synthesis, self-assembly, and application

This study is aimed to develop a well-defined ABC triblock terpolymer, poly(ethylethylene phosphate)-block-poly(e-caprolactone)-block-poly[2-(dimethylamino)ethyl methacrylate] (PEEP-b-PCL-b-PDMAEMA), for co-encapsulating anticancer drug doxorubicin (DOX) and DNA to form polyplexes. The terpolymer is first synthesized via a combination of ring-opening polymerization and atom-transfer radical polymerization techniques, and characterized by 1H NMR and gel permeation chromatography. Subsequently, the self-assembly behavior of the terpolymer and the micelles loaded with DOX or DNA are investigated by dynamic light scattering, ζ potential, transmission electron microscopy, and gel retardation assay, respectively. In vitro release study reveals that much more DOX is released at pH 5.0 than that at pH 7.4 in the same period. The simultaneous delivery of DOX and green fluorescent protein (GFP)-labeled DNA is studied by a fluorescence microscope and the results demonstrate that both drug and GFP–DNA can be efficiently delivered into HeLa cells. This system presents a practical and promising carrier for the co-delivery of drugs and genes. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3005–3016

Synthesis and characterization of a biodegradable ABC triblock terpolymer as co-delivery carrier of doxorubicin and DNA

Abstract In situ changes in the nanofriction and microstructures of ionic liquids (ILs) on uncharged and charged surfaces have been investigated using colloid probe atomic force microscopy (AFM) and molecular dynamic (MD) simulations. Two representative ILs, [BMIM][BF 4 ] (BB) and [BMIM][PF 6 ] (BP), containing a common cation, were selected for this study. The torsional resonance frequency was captured simultaneously when the nanoscale friction force was measured at a specified normal load; and it was regarded as a measure of the contact stiffness, reflecting in situ changes in the IL microstructures. A higher nanoscale friction force was observed on uncharged mica and highly oriented pyrolytic graphite (HOPG) surfaces when the normal load increased; additionally, a higher torsional resonance frequency was detected, revealing a higher contact stiffness and a more ordered IL layer. The nanofriction of ILs increased at charged HOPG surfaces as the bias voltage varied from 0 to 8 V or from 0 to —8 V. The simultaneously recorded torsional resonance frequency in the ILs increased with the positive or negative bias voltage, implying a stiffer IL layer and possibly more ordered ILs under these conditions. MD simulation reveals that the [BMIM] + imidazolium ring lies parallel to the uncharged surfaces preferentially, resulting in a compact and ordered IL layer. This parallel “sleeping” structure is more pronounced with the surface charging of either sign, indicating more ordered ILs, thereby substantiating the AFM-detected stiffer IL layering on the charged surfaces. Our in situ observations of the changes in nanofriction and microstructures near the uncharged and charged surfaces may facilitate the development of IL-based applications, such as lubrication and electrochemical energy storage devices, including supercapacitors and batteries. 

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Ionic liquids on uncharged and charged surfaces: In situ microstructures and nanofriction

Abstract Very recently, two-dimensional quantum dots (2D QDs) have been pioneeringly investigated as lubricant additives, which exhibit superior friction-reducing and wear resistance. Compared with 2D nanoparticles, 2D QDs possess small size (∼10 nm) and abundant active groups. These distinguished advantages enable them to quickly disperse into common lube mediums and maintain long-term storage stability. The good dispersion stability of 2D QDs not only effectively improves their embedding capacity, but also enables continuous supplements of lubricants during the sliding process. Therefore, 2D QDs are attracting increasing research interest as efficient lubricants with desirable service life. In this review, we focus on the latest studies of 2D QDs as liquid lubricant additives (both in polar and nonpolar mediums), self-lubricating solid coatings and gels, etc. Various advanced strategies for synthesis and modification of 2D QDs are summarized. A comprehensive insight into the tribological behavior of a variety of 2D QDs together with the associated mechanism is reviewed in detail. The superior lubricating performances of 2D QDs are attributed to various mechanisms, including rolling effect, self-mending performance, polishing effect, tribofilm formation, nanostructure transfer and synergistic effects, etc. Strategies for friction modulation of 2D QDs, including internal factors (surface modification, elemental doping) and extrinsic factors (counter surfaces, test conditions) are discussed, special attentions for achieving intelligent tribology toward superlubricity and bio-engineering, are also included. Finally, the future challenges and research directions regarding QDs as lubricants conforming to the concept of “green tribology” toward a sustainable society are discussed. 

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Delivering quantum dots to lubricants: Current status and prospect

This invention relates to a fluorine cationoid latices and preparation method. The invention takes amphipathy fluorine block polymer as macromolecule emulsifying agent to apply to fine emulsion polymerization, obtain a kind of emulsion particle that has fluorine chain segment and protonated chain segment on surface, namely fluorine cationoid latices. This invention overcomes the traditional process shortcoming of high production cost, at the same time proceed functionalization to the emulsion particle.

Wenling Zhang

Papers

Biocompatible and pH-responsive triblock copolymer mPEG-b-PCL-b-PDMAEMA: Synthesis, self-assembly, and application

Synthesis and characterization of a biodegradable ABC triblock terpolymer as co-delivery carrier of doxorubicin and DNA

Ionic liquids on uncharged and charged surfaces: In situ microstructures and nanofriction

Delivering quantum dots to lubricants: Current status and prospect

Fluorine-contained cation type emulsion and preparing method