Search results for "Peg"
showing 10 items of 460 documents
Determining the selective impregnation of waterlogged archaeological woods with poly(ethylene) glycols mixtures by differential scanning calorimetry
2012
The differential scanning calorimetry (DSC) technique was demonstrated to be a reliable and fast tool for the investigation of the selective impregnation of archaeological woods with poly(ethylene) glycols (PEGs) mixtures. To this aim, waterlogged archaeological woods were impregnated by using aqueous mixtures of PEG 4000 and PEG 400 as well as mixtures of these polymers in the melt state. The efficiency of the treatments was also estimated by determining the total consolidant content entrapped into the cavities of degraded wood by means of DSC and thermogravimetry.
“Clickable PEG” via anionic copolymerization of ethylene oxide and glycidyl propargyl ether
2017
A straight forward synthesis of poly(ethylene glycol) (PEG) with multiple alkyne groups distributed along the polymer chain is introduced. Direct access to clickable PEG is achieved by the monomer-activated anionic ring-opening copolymerization (AROP) of ethylene oxide (EO) with glycidyl propargyl ether (GPgE). Notably for successful polymerization no protection of the alkyne unit is required owing to the mild reaction conditions. Defined PEG-co-PGPgE and PGPgE (co)polymers with PDIs of 1.18–1.60 and molecular weights of Mn = 3000–9500 g mol−1 were prepared. In situ1H NMR kinetic studies revealed remarkably disparate reactivity ratios of rEO = 14.8 and rGPgE = 0.076, representing a pronounc…
Functional PEG-based polymers with reactive groups via anionic ROP of tailor-made epoxides
2012
In this review article functional epoxide monomers that are suitable for controlled ring-opening polymerization (ROP) are discussed. Functional epoxides possess reactive groups, which either are directly accessible or carry suitable protective groups that can be removed in a facile one-step reaction after polymerization. The methods used to obtain linear, functional aliphatic polyethers rely on living polymerization techniques for the synthesis of well-defined structures. Materials properties, such as thermo-responsive behavior in combination with different functional groups that can be addressed selectively, render these novel materials interesting for a variety of applications.
Automated Large-Scale Synthesis of Supramolecular Oligo(p-benzamide) Block Copolymers
2007
A fully automated large-scale synthesis procedure has been developed that allows the preparation of supramolecular rod−coil copolymers on a 100 g scale. The new reaction cycle allows the stepwise growth of oligo(p-benzamide)s onto the chain end of amine-terminated polymers. Amine-terminated poly(ethylene glycol) (PEG, Mn = 5000 g mol-1) and poly(styrene) (PS, Mn = 2950 g mol-1) were prepared, and an octa(p-benzamide) oligomer block was grown from the chain end in an automated computer-controlled reaction cycle. Plotting the apparent molecular weight of the PEG copolymer against the number of reaction cycles revealed a linear relationship, which emphasized the high level of control this meth…
Introducing PeptoPlexes: Polylysine-block-Polysarcosine Based Polyplexes for Transfection of HEK 293T Cells
2014
A series of well-defined polypeptide-polypeptoid block copolymers based on the body's own amino acids sarcosine and lysine are prepared by ring opening polymerization of N-carboxyanhydrides. Block lengths were varied between 200-300 for the shielding polysarcosine block and 20-70 for the complexing polylysine block. Dispersity indexes ranged from 1.05 to 1.18. Polylysine is polymerized with benzyloxycarbonyl as well as trifluoroacetyl protecting groups at the ϵ-amine group and optimized deprotection protocols for both groups are reported. The obtained block ionomers are used to complex pDNA resulting in the formation of polyplexes (PeptoPlexes). The PeptoPlexes can be successfully applied i…
Synthesis and characterization of bisalkylated polysarcosine-based lipopolymers
2019
The use of PEGylated lipids for the synthesis of stealth liposomes and lipid formulations for nucleic acid delivery has promoted the development of nanoparticle based drugs for cancer therapy, and chronic diseases. Moreover, several other nanomedicines based on these materials have advanced into clinical trails. This enormous success, however, has recently been compromised by the occurrence of immune responses towards PEG, which render pharmacokinetics and can substantially reduce the therapeutic efficiency of drugs. Therefore, alternatives for PEGylated lipids with comparable or even identical solution properties are required. In this work, we report the synthesis of polysarcosine based li…
Impact of surface state on polyethylene glycol conformation confined inside a nanopore.
2021
Solid-state nanopores are a promising platform for characterizing proteins. In order to improve their lifetime and prevent fouling, Polyethylene Glycol (PEG) grafting is one of the most efficient and low-cost solutions. Different models to calculate the PEG thickness do not consider their interaction with the nanopore inner surface nor the effect of confinement. Here, we investigate by molecular dynamic simulation the PEG conformation inside a nanopore in the case of hydrophobic and hydrophilic nanopores. Our results reveal that the nanopore inner surface plays a role in the PEG organization and, thus, in the speed of the salt constituent. The resulting pair interaction between PEG and its …
Dispersion of titanate nanotubes for nanomedicine: comparison of PEI and PEG nanohybrids.
2014
In the present study, we report the dispersion of titanate nanotubes (TiONts) via polymer grafting (PolyEthylene Glycol, PEG) or polymer adsorption (polyethylene imine, PEI) where different TiONts/polymer ratios have been investigated. The TiONts/PEI and TiONts/PEG nanohybrids were characterized by scanning and transmission electron microscopy as well as by zeta potential measurements in order to determine both their dispersion state and stability in water (at different pH for zetametry). The nature of the chemical bonds at the surface of these nanohybrids was investigated by Fourier-transformed infrared (FTIR) spectroscopy while the grafting densities of PEG on the nanotubes were quantifie…
Hydrophilic and hydrophobic copolymers of a polyasparthylhydrazide bearing positive charges as vector for gene therapy
2008
BACKGROUND: The design of polymeric vectors for gene delivery provided with specific properties is one of the most critical aspects for a successful gene therapy. These polymers should be biocompatible as well as able to carry efficiently DNA to target tissues and to transfect it into cells. RESULTS: The formation of complexes of poly[(α,β-asparthylhydrazide)–poly(ethylene glycol)] and poly[(α,β-asparthylhydrazide)–hexadecylamine] copolymers functionalised with glycidyltrimethylammonium chloride (PAHy–PEG-GTA and PAHy–C16-GTA, respectively) with DNA was studied. The effects of the introduction of hydrophilic (PEG) or hydrophobic (C16) moieties on the chains of PAHy–GTA copolymers, such as t…
Proteomic and Lipidomic Analysis of Nanoparticle Corona upon Contact with Lung Surfactant Reveals Differences in Protein, but Not Lipid Composition.
2015
Pulmonary surfactant (PS) constitutes the first line of host defense in the deep lung. Because of its high content of phospholipids and surfactant specific proteins, the interaction of inhaled nanoparticles (NPs) with the pulmonary surfactant layer is likely to form a corona that is different to the one formed in plasma. Here we present a detailed lipidomic and proteomic analysis of NP corona formation using native porcine surfactant as a model. We analyzed the adsorbed biomolecules in the corona of three NP with different surface properties (PEG-, PLGA-, and Lipid-NP) after incubation with native porcine surfactant. Using label-free shotgun analysis for protein and LC-MS for lipid analysis…