Showing papers on "Ethylene glycol published in 2011"
TL;DR: In-situ high-resolution transmission electron microscopy (HRTEM) studies of the structural transformations that occur during the synthesis of carbon-coated LiFePO4 and heat treatment to elevated temperatures were conducted in two different electron microscopes as discussed by the authors.
3,037 citations
TL;DR: In the in vivo T(1)-weighted magnetic resonance imaging (MRI), ESIONs showed longer circulation time than the clinically used gadolinium complex-based contrast agent, enabling high-resolution imaging and demonstrating the potential of ESions as T( 1) MRI contrast agents in clinical settings.
Abstract: Uniform and extremely small-sized iron oxide nanoparticles (ESIONs) of < 4 nm were synthesized via the thermal decomposition of iron–oleate complex in the presence of oleyl alcohol. Oleyl alcohol lowered the reaction temperature by reducing iron–oleate complex, resulting in the production of small-sized nanoparticles. XRD pattern of 3 nm-sized nanoparticles revealed maghemite crystal structure. These nanoparticles exhibited very low magnetization derived from the spin-canting effect. The hydrophobic nanoparticles can be easily transformed to water-dispersible and biocompatible nanoparticles by capping with the poly(ethylene glycol)-derivatized phosphine oxide (PO-PEG) ligands. Toxic response was not observed with Fe concentration up to 100 μg/mL in MTT cell proliferation assay of POPEG-capped 3 nm-sized iron oxide nanoparticles. The 3 nm-sized nanoparticles exhibited a high r1 relaxivity of 4.78 mM–1 s–1 and low r2/r1 ratio of 6.12, demonstrating that ESIONs can be efficient T1 contrast agents. The high r...
771 citations
TL;DR: The demonstrated ability of melanin-like nanoparticles to reduce 2,2-diphenyl-1-picrylhydrazyl (DPPH) suggests free radical scavenging activity of the material.
634 citations
TL;DR: PEGylation or covalent attachment of poly(ethylene glycol) improves the pharmacokinetic properties of protein drugs, resulting in improved patient quality of life and in vivo circulation lifetimes and dosages.
584 citations
TL;DR: Encapsulation and controlled release of small molecules such as rhodamine B and proteins such as lysozyme have been successfully carried out, demonstrating the potential biomedical applications of these chitosan-based dynamic hydrogels.
545 citations
TL;DR: The advantages of oligo(ethylene glycol)‐based (co)polymers for preparing thermoresponsive materials as diverse as polymer‐enzyme bio‐hybrids, injectable hydrogels, capsules for drug‐release, modified magnetic particles for in vivo utilization, cell‐culture substrates, antibacterial surfaces, or stationary phases for bioseparation are described.
Abstract: We describe here the advantages of oligo(ethylene glycol)-based (co)polymers for preparing thermoresponsive materials as diverse as polymer-enzyme bio-hybrids, injectable hydrogels, capsules for drug-release, modified magnetic particles for in vivo utilization, cell-culture substrates, antibacterial surfaces, or stationary phases for bioseparation. Oligo(ethylene glycol) methacrylates (OEGMAs) can be (co)polymerized using versatile and widely-applicable methods of polymerization such as atom transfer radical polymerization (ATRP) of reversible addition-fragmentation chain-transfer (RAFT) polymerization. Thus, the molecular structure and therefore the stimuli-responsive properties of these polymers can be precisely controlled. Moreover, these stimuli-responsive macromolecules can be easily attached to–or directly grown from–organic, inorganic or biological materials. As a consequence, the OEGMA synthetic platform is today a popular option for materials design. The present research news summaries the progress of the last two years.
373 citations
TL;DR: In this paper, primary amine modified graphene (NH2-G) is used to obtain a high specific capacitance with a current density of 0.4 A/g, superior over commercially available GO, chemically reduced GO, activated carbon, and CNT.
372 citations
TL;DR: In this article, different amounts of Al2O3 nanoparticle have been added into these base fluids and its effects on the heat transfer performance of the car radiator have been determined experimentally.
341 citations
TL;DR: In this article, a novel polyester from renewable resources based on 2,5-dicarboxylic acid and several diols were synthesized and characterized using different polycondensation techniques.
Abstract: Novel polyesters from renewable resources based on 2,5-dicarboxylic acid and several diols were synthesized and characterized using different polycondensation techniques. The aliphatic diols were sufficiently volatile to allow the use of polytransesterifications, which gave high-molecular weight semicrystalline materials with good thermal stability. In particular, the polyester based on ethylene glycol displayed properties comparable with those of its aromatic counterpart, poly(ethylene terephthalate), namely, the most important industrial polyester. The use of isosorbide gave rise to amorphous polymers with very stiff chains and hence a high glass transition temperature and an enhanced thermal stability. The interfacial polycondensation between the acid dichloride and hydroquinone produced a semicrystalline material with features similar to those of entirely aromatic polyesters, characterized essentially by the absence of melting and poor solubility, both associated with their remarkable chain rigidity. The replacement of hydroquinone with the corresponding benzylic diol was sufficient to provide a more tractable polyester. This study provided ample evidence in favor of the exploitation of furan monomers as renewable alternatives to fossil-based aromatic homologs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
318 citations
TL;DR: The combination of PEG and nHAp nanoparticles significantly improved the physical and chemical hydrogel properties as well as some biological characteristics such as osteoblast cell adhesion.
298 citations
TL;DR: Wang et al. as discussed by the authors, 2011CBA00508; Key Scientific Project of Fujian Province [2009HZ0002-1] and National Natural Science Foundation of China [20873108, 20923004]
TL;DR: The stability and compatibility demonstrated in blood suggest that self-assembled polymeric micelles may be stable in vivo, which is critical for intravenous drug delivery applications.
Abstract: The stability of polymeric nanoparticles in serum is critical to their use in drug delivery where dilution after intravenous injection often results in nanoparticle disassembly and drug unloading; however, few investigate this in biologically relevant media. To gain greater insight into nanoparticle stability in blood, the stability of self-assembled polymeric micelles of poly(d,l-lactide-co-2-methyl-2-carboxytrimethylene carbonate)-g-poly(ethylene glycol), P(LA-co-TMCC)-g-PEG, were tested in both serum and individual serum protein solutions. By encapsulating Forster resonance energy transfer pairs and following their release by fluorescence, these micelles demonstrated excellent thermodynamic and kinetic stability in the presence of serum. Further analyses by fast protein liquid chromatography and dynamic light scattering confirmed these data. Moreover, these micelles are compatible with red blood cells, as shown by a hemolysis assay. The stability and compatibility demonstrated in blood suggest that the...
TL;DR: A direct, head-to-head comparison of the efficacy of a zwitterionic versus a poly(ethylene glycol), PEG, coating in preventing protein adsorption to silica and aggregation of silica nanoparticles is presented.
Abstract: A direct, head-to-head comparison of the efficacy of a zwitterionic versus a poly(ethylene glycol), PEG, coating in preventing protein adsorption to silica and aggregation of silica nanoparticles is presented. The same siloxane coupling chemistry was employed to yield surfaces with similar coverages of both types of ligand. Nanoparticle and planar surfaces were challenged with salt, serum, lysozyme, and serum albumin at 25 and 37 °C. While both types of surface modification are highly effective in preventing protein adsorption and nanoparticle aggregation, the zwitterion provided monolayer-type coverage with minimal thickness, whereas the PEG appeared to yield a more three-dimensional coating. The mechanism for adsorption resistance is thought to be based on preventing ion pairing between protein and surface charges, which releases counterions and water molecules, an entropic driving force enough to overcome a disfavored enthalpy of adsorption.
TL;DR: In this paper, the role of polyol types in the nucleation and growth of metallic nanoparticles was investigated and the relationship between synthesis conditions, crystal morphology, and theoretical modeling of copper and nickel nanoparticles prepared by a modified polyol process was discussed.
Abstract: This paper discusses the relationship between synthesis conditions, crystal morphology, and theoretical modeling of copper and nickel nanoparticles prepared by a modified polyol process. The polyol serves as a solvent, a reducing agent, and a capping agent, and we investigate the role several polyol types play in the nucleation and growth of metallic nanoparticles. The nanoparticles are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Our results demonstrate that changing the solvent system from a short chain polyol (ethylene glycol) to a long chain polyol (tetraethylene glycol) greatly affects the resulting morphology of copper nanoparticles. These results suggest that the polyol is playing a major role as an in situ capping agent and that the various polyol chain lengths in-turn result in various particle morphologies by directly altering the nucleation and growth steps. We were also able to use theoretical modeling to investig...
TL;DR: In this paper, polyamide reverse osmosis (XLE) and nanofiltration (NF90) membranes were modified by grafting poly(ethylene glycol) (PEG) diglycidyl ether(PEGDE) to their top surfaces from aqueous solution.
TL;DR: The combinations of properties such as elasticity, stiffness, interconnected network, adhesiveness to surfaces and bio-adhesion to cells provide inspiration and opportunities to engineer mechanically strong and elastic tissue matrixes for orthopedic, craniofacial and dental applications.
TL;DR: In vitro methyl thiazolyl tetrazolium (MTT) assays indicated that the NGs were biocompatible, and DOX-loaded NG showed higher cellular proliferation inhibition towards GSH pretreated HeLa cells than that of non-pretreated cells.
TL;DR: The results of this work suggest that 2PP may be used to polymerize poly(ethylene glycol)-based materials into three-dimensional structures with well-defined geometries that mimic the physical and biological properties of native cell environments.
TL;DR: The concomitant incorporation of antifouling hydrophilic brushes and antibacterial enzymes or peptides onto metal surfaces via catecholic anchors should be readily adaptable to other metal substrates, and is potentially useful for biomedical and biomaterial applications.
Abstract: An environmentally benign approach to impart stainless steel (SS) surfaces with antifouling and antibacterial functionalities was described. Surface-initiated atom transfer radical polymerization (ATRP) of poly(ethylene glycol) monomethacrylate) (PEGMA) from the SS surface-coupled catecholic l-3,4-dihydroxyphenylalanine (DOPA) with terminal alkyl halide initiator was first carried out, followed by the immobilization of lysozyme at the chain ends of poly(ethylene glycol) branches of the grafted PEGMA polymer brushes. The functionalized SS surfaces were shown to be effective in preventing bovine serum albumin (BSA) adsorption and in reducing bacterial adhesion and biofilm formation. The surfaces also exhibited good bactericidal effects against Escherichia coli and Staphylococcus aureus. The concomitant incorporation of antifouling hydrophilic brushes and antibacterial enzymes or peptides onto metal surfaces via catecholic anchors should be readily adaptable to other metal substrates, and is potentially usef...
TL;DR: In this paper, the selective hydrogenolysis of biomass-derived xylitol to ethylene glycol and glycol was carried out on different catalysts in the presence of Ca(OH)2.
TL;DR: The results indicate that the volume phase transition temperature (VPTT), thermally induced deswelling ratio, and acid-triggered swelling ratio of the nanogels are closely relevant to their compositions and crosslinking degrees.
TL;DR: Reversible addition−fragmentation chain transfer (RAFT) aqueous dispersion polymerization was used to synthesize a novel type of core−shell nanogel containing linear poly( methylene glycol) (PEG) and/or nonlinear polymers with oligo(ethylene gly col) side chains with enhanced stability in comparison with molecularly dissolved polymers.
Abstract: Reversible addition−fragmentation chain transfer (RAFT) aqueous dispersion polymerization was used to synthesize a novel type of core−shell nanogel containing linear poly(ethylene glycol) (PEG) and/or nonlinear polymers with oligo(ethylene glycol) side chains. These nanogels with low polydispersities were synthesized efficiently with tunable sizes and thermosensitivities. The nanogels containing nonlinear polymers with oligo(ethylene glycol) side chains as the shell had enhanced stability during freeze−thawing process and in biologically relevant solutions including 1.5 M NaCl, 1% bovine serum albumin (BSA) and 100% fetal bovine serum (FBS) solutions. Aminolysis and hydrolysis of the chain transfer agents (CTAs) in the nanogels were studied and the nanogels exhibited enhanced stability in comparison with molecularly dissolved polymers. The chemical stability of the CTAs in the nanogels was well-correlated with the in vitro cell viability studies of the nanogels using lung cancer cells.
TL;DR: In this paper, the authors used methyl triphenyl phosphunium bromide as salt and three different hydrogen-bond donors, namely, glycerol, ethylene glycol and triethylene glycol, to synthesize three deep eutectic solvents (DESs).
Abstract: Biodiesel is a remarkable alternative to the decreasing resources for fossil fuels. One of the critical steps in producing biodiesel is its purification from the byproduct glycerol. The content of glycerol permissible must pass the EN 14214 and ASTM D6751 international biodiesel standards. In this work, methyl triphenyl phosphunium bromide as salt and three different hydrogen-bond donors, namely, glycerol, ethylene glycol, and triethylene glycol, were selected to synthesize three deep eutectic solvents (DESs). These DESs were employed as the solvent for the removal of glycerol from palm-oil-based biodiesel. The effects of DES type on the removal of free glycerol, bound glycerol, and total glycerol were investigated. The results revealed that the ethylene glycol DESs and triethylene glycol DESs were successful in removing all free glycerol from the palm-oil-based biodiesel. All tested DESs were able to reduce the content of monoglycerides (MGs) and diglycerides (DGs). Moreover, all used DESs had the tenden...
TL;DR: Although associated with higher synthesis costs, dendritic macromolecules are considered to be an attractive alternative to linear polymers for surface (bio)functionalization in view of their spontaneous formation of ultrathin, confluent, and nonfouling monolayers at room temperature and their outstanding ability to present functional ligands at high surface densities.
Abstract: This work covers the synthesis of second-generation, ethylene glycol dendrons covalently linked to a surface anchor that contains two, three, or four catechol groups, the molecular assembly in aqueous buffer on titanium oxide surfaces, and the evaluation of the resistance of the monomolecular adlayers against nonspecific protein adsorption in contact with full blood serum. The results were compared to those of a linear poly(ethylene glycol) (PEG) analogue with the same molecular weight. The adsorption kinetics as well as resulting surface coverages were monitored by ex situ spectroscopic ellipsometry (VASE), in situ optical waveguide lightmode spectroscopy (OWLS), and quartz crystal microbalance with dissipation (QCM-D) investigations. The expected compositions of the macromolecular films were verified by X-ray photoelectron spectroscopy (XPS). The results of the adsorption study, performed in a high ionic strength ("cloud-point") buffer at room temperature, demonstrate that the adsorption kinetics increase with increasing number of catechol binding moieties and exceed the values found for the linear PEG analogue. This is attributed to the comparatively smaller and more confined molecular volume of the dendritic macromolecules in solution, the improved presentation of the catechol anchor, and/or their much lower cloud-point in the chosen buffer (close to room temperature). Interestingly, in terms of mechanistic aspects of "nonfouling" surface properties, the dendron films were found to be much stiffer and considerably less hydrated in comparison to the linear PEG brush surface, closer in their physicochemical properties to oligo(ethylene glycol) alkanethiol self-assembled monolayers than to conventional brush surfaces. Despite these differences, both types of polymer architectures at saturation coverage proved to be highly resistant toward protein adsorption. Although associated with higher synthesis costs, dendritic macromolecules are considered to be an attractive alternative to linear polymers for surface (bio)functionalization in view of their spontaneous formation of ultrathin, confluent, and nonfouling monolayers at room temperature and their outstanding ability to present functional ligands (coupled to the termini of the dendritic structure) at high surface densities.
TL;DR: It is shown that installation of a relatively small, hydrophilic (R)-diethylene glycol ("miniPEG", R-MP) unit at the γ-backbone transforms a randomly folded PNA into a right-handed helix, which has important implications for the future design and application of PNA in biology, biotechnology, and medicine.
Abstract: Developed in the early 1990s, peptide nucleic acid (PNA) has emerged as a promising class of nucleic acid mimic because of its strong binding affinity and sequence selectivity toward DNA and RNA and resistance to enzymatic degradation by proteases and nucleases; however, the main drawbacks, as compared to other classes of oligonucleotides, are water solubility and biocompatibility. Herein we show that installation of a relatively small, hydrophilic (R)-diethylene glycol (“miniPEG”, R-MP) unit at the γ-backbone transforms a randomly folded PNA into a right-handed helix. Synthesis of optically pure R-MPγPNA monomers is described, which can be accomplished in a few simple steps from a commercially available and relatively cheap Boc-l-serine. Once synthesized, R-MPγPNA oligomers are preorganized into a right-handed helix, hybridize to DNA and RNA with greater affinity and sequence selectivity, and are more water soluble and less aggregating than the parental PNA oligomers. The results presented herein have im...
TL;DR: The PIZOF structure is highly tolerant towards the variation of R(1) and R(2) and offers a facile tuning of the chemical environment within the pores, and is stable up to 325 °C in air as determined by using thermogravimetry and powder X-ray diffraction.
Abstract: We present the synthesis and characterization of porous interpenetrated zirconium-organic frameworks (PIZOFs), a new family of metal-organic frameworks obtained from ZrCl(4) and the rodlike dicarboxylic acids HO(2)C[PE-P(R(1),R(2))-EP]CO(2) H that consist of alternating phenylene (P) and ethynylene (E) units. The substituents R(1),R(2) were broadly varied (alkyl, O-alkyl, oligo(ethylene glycol)), including postsynthetically addressable substituents (amino, alkyne, furan). The PIZOF structure is highly tolerant towards the variation of R(1) and R(2). This together with the modular synthesis of the diacids offers a facile tuning of the chemical environment within the pores. The PIZOF structure was solved from single-crystal X-ray diffraction analysis. The PIZOFs are stable under ambient conditions. PIZOF-2, the PIZOF prepared from HO(2)C[PE-P(OMe,OMe)-EP]CO(2)H, served as a prototype to determine thermal stability and porosity. It is stable up to 325 °C in air as determined by using thermogravimetry and powder X-ray diffraction. Argon sorption isotherms on PIZOF-2 revealed a Brunauer-Emmett-Teller (BET) surface area of 1250 m(2) g(-1) and a total pore volume of 0.68 cm(3) g(-1).
TL;DR: In this article, a simplified wet-spinning process for the production of continuous poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fibers is reported.
Abstract: A simplified wet-spinning process for the production of continuous poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) fibers is reported. Conductivity enhancement of PEDOT:PSS fibers up to 223 S cm -1 has been demonstrated when these fibers are exposed to ethylene glycol as a post-synthesis processing step. In a new spinning approach it is shown that by employing a spinning formulation consisting of an aqueous blend of PEDOT:PSS and poly(ethlylene glycol), the need for post-spinning treatment with ethylene glycol is eliminated. With this approach, 30-fold conductivity enhancements from 9 to 264 S cm-1 are achieved with respect to an untreated fiber. This one-step approach also demonstrates a significant enhancement in the redox properties of the fibers. These improvements are attributed to an improved molecular ordering of the PEDOT chains in the direction of the fiber axis and the consequential enrichment of linear (or expanded-coil like) conformation to preference bipolaronic electronic structures as evidenced by Raman spectroscopy, solid-state electron spin resonance (ESR) and in situ electrochemical ESR studies. A facile one-step fiber wet-spinning process to fabricate continuous and highly conducting fibers from poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)-poly(ethylene glycol)(PEDOT:PSS-PEG) blend is described. Improvements in electrical conductivity and electrochemical properties are due to the improved molecular ordering of the PEDOT chains in the direction of the fiber axis and the consequential enrichment of linear (or expanded-coil-like) conformation to preference bipolaronic electronic structures.
TL;DR: In this paper, the authors proposed multifunctional linear copolymers (mf-PEGs) based on EO and appropriate epoxide comonomers for bioactive macromolecular hybrid structures.
Abstract: In the rapidly evolving multidisciplinary field of polymer therapeutics, tailored polymer structures represent the key constituent to explore and harvest the potential of bioactive macromolecular hybrid structures. In light of the recent developments for anticancer drug conjugates, multifunctional polymers are becoming ever more relevant as drug carriers. However, the potentially best suited polymer, poly(ethylene glycol) (PEG), is unfavorable owing to its limited functionality. Therefore, multifunctional linear copolymers (mf-PEGs) based on ethylene oxide (EO) and appropriate epoxide comonomers are attracting increased attention. Precisely engineered via living anionic polymerization and defined with state-of-the-art characterization techniques-for example real-time (1)H NMR spectroscopy monitoring of the EO polymerization kinetics-this emerging class of polymers embodies a powerful platform for bio- and drug conjugation.
TL;DR: The ability to promote angiogenesis in tissue engineered constructs using a covalently-bound small peptide rather than a large protein is shown and may point to an advance in designing biomimetic cellular environments.
TL;DR: In this article, the authors have synthesized Al-5wt%Zn nanoparticles by mechanical alloying, characterized these nanoparticles using X-ray diffraction and scanning and transmission electron microscopy.