Search results for "Poly(ethylene glycol)"
showing 10 items of 337 documents
Wavelength-Selective Softening of Hydrogel Networks.
2021
Photoresponsive hydrogels hold key potential in advanced biomedical applications including tissue engineering, regenerative medicine, and drug delivery, as well as intricately engineered functions such as biosensing, soft robotics, and bioelectronics. Herein, the wavelength-dependent degradation of bio-orthogonal poly(ethylene glycol) hydrogels is reported, using three selective activation levels. Specifically, three chromophores are exploited, that is, ortho-nitrobenzene, dimethyl aminobenzene, and bimane, each absorbing light at different wavelengths. By examining their photochemical action plots, the wavelength-dependent reactivity of the photocleavable moieties is determined. The wavele…
Ruthenium-Containing Block Copolymer Assemblies: Red-Light-Responsive Metallopolymers with Tunable Nanostructures for Enhanced Cellular Uptake and An…
2015
The use of self-assembled nanostructures consisting of red-light-responsive Ru(II)-containing block copolymers (BCPs) for anticancer phototherapy is demonstrated. Three Ru-containing BCPs with different molecular weights are synthesized. Each BCP contains a hydrophilic poly(ethylene glycol) block and an Ru-containing block. In the Ru-containing block, more than half of the side chains are coordinated with [Ru(2,2':6',2''-terpyridine)(2,2'-biquinoline)](2+) , resulting in more than 40 wt% Ru complex in the BCPs. The Ru complex acts as both a red-light-cleavable moiety and a photoactivated prodrug. Depending on their molecular weights, the BCPs assemble into micelles, vesicles, and large comp…
Advancements in Sustainable PVDF Copolymer Membrane Preparation Using Rhodiasolv® PolarClean As an Alternative Eco-Friendly Solvent
2021
In this work, Rhodiasolv® PolarClean was employed as a more sustainable solvent for the preparation of poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) flat sheet membranes via phase inversion technique by coupling vapour induced phase separation (VIPS) and non-solvent induced phase separation (NIPS) processes. Preliminary calculations based on Hansen solubility parameters well predicted the solubilization of the polymer in the selected solvent. The effect of exposure time on humidity and the influence of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and sulfonated polyether sulfone (S-PES) on membrane properties and performance, were evaluated. Three different coagulation …
Protein corona composition of poly(ethylene glycol)- and poly(phosphoester)-coated nanoparticles correlates strongly with the amino acid composition …
2017
Extensive molecular dynamics simulations reveal that the interactions between proteins and poly(ethylene glycol) (PEG) can be described in terms of the surface composition of the proteins. PEG molecules accumulate around non-polar residues while avoiding the polar ones. A solvent-accessible-surface-area model of protein adsorption accurately fits a large set of data on the composition of the protein corona of poly(ethylene glycol)- and poly(phosphoester)-coated nanoparticles recently obtained by label-free proteomic mass spectrometry.
Amoxicillin-loaded polyethylcyanoacrylate nanoparticles: influence of PEG coating on the particle size, drug release rate and phagocytic uptake.
2001
Polyethyleneglycol (PEG)-coated polyethylcyanoacrylate (PECA) nanoparticles loaded with amoxicillin were prepared and the influence of the PEG coating on the particle size, zeta potential, drug release rate and phagocytic uptake by murine macrophages was studied. Experimental results show that this colloidal drug delivery system could be useful for intravenous or oral administration. The profile of amoxicillin release from PECA nanoparticles system was studied under various conditions similar to those of some corporeal fluids. In all these experiments, amoxicillin release in the free form was studied by HPLC analysis. Experimental results showed that at pH 7.4 drug release rises when molecu…
Structure–property relationship and controlled drug release from multiphasic electrospun carvacrol-embedded polylactic acid/polyethylene glycol and p…
2018
Electrospinning technologies gained considerable interest over the last decade. In this study, it is proposed a systematic study of polylactic acid/polyethylene glycol (PLA/PEG) and polylactic acid/polyethylene oxide (PLA/PEO) electrospun blends at different concentrations. The effect of blend composition and PEG molecular weight on the morphological and mechanical properties of the mats was evaluated. Furthermore, the kinetic release of carvacrol as model drug in phosphate buffer saline at 37℃ was studied and the data were then fitted using an exponential model. The scanning electron microscopy revealed that the morphology of the mats was strongly dependent on the relative ratio PLA:PEG, …
Evaluation of biodegradability on polyaspartamide-polylactic acid based nanoparticles by chemical hydrolysis studies
2015
Here, the synthesis of two graft copolymers based on ?,?-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA) and poly(lactic acid) (PLA), the O-(2-aminoethyl)-O'-galactosyl polyethylene glycol (GAL-PEG-NH2) or the methoxypolyethylene glycol amine (H2N-PEG-OCH3) is described. Starting from the obtained PHEA-PLA-PEG-GAL and PHEA-PLA-PEG copolymers, polymeric nanoparticles were prepared by high pressure homogenization-solvent evaporation method. To demonstrate their biodegradability as a function of the matrix composition, a chemical stability study was carried out until 21 days by incubating systems in two media mimicking physiological compartments (pH 7.4 and pH 5.5). The degradability of both nan…
Cleavable Polyethylene Glycol: 3,4-Epoxy-1-butene as a Comonomer to Establish Degradability at Physiologically Relevant pH.
2016
Polyethylene glycol (PEG) has been used for decades to improve the pharmacokinetic properties of protein drugs, and several PEG-protein conjugates are approved by the FDA. However, the nondegradability of PEG restricts its use to a limiting molecular weight to permit renal excretion. In this work, we introduce a simple strategy to overcome the nondegradability of PEG by incorporating multiple pH-sensitive vinyl ether moieties into the polyether backbone. Copolymerization of 3,4-epoxy-1-butene (EPB) with ethylene oxide via anionic ring-opening polymerization (AROP) provides access to allyl moieties that can be isomerized to pH-cleavable propenyl units (isoEPB). Well-defined P(EPB-co-EG) copo…
Artificial neural network based particle size prediction of polymeric nanoparticles.
2017
Particle size of nanoparticles and the respective polydispersity are key factors influencing their biopharmaceutical behavior in a large variety of therapeutic applications. Predicting these attributes would skip many preliminary studies usually required to optimize formulations. The aim was to build a mathematical model capable of predicting the particle size of polymeric nanoparticles produced by a pharmaceutical polymer of choice. Polymer properties controlling the particle size were identified as molecular weight, hydrophobicity and surface activity, and were quantified by measuring polymer viscosity, contact angle and interfacial tension, respectively. A model was built using artificia…
Routine preparation of air-dried negatively stained and unstained specimens on holey carbon support films: a review of applications.
2002
Several representative examples are given of the successful application of negative staining across the holes of holey carbon support films using 5% (w/v) ammonium molybdate solution containing trehalose. The inclusion of 0.1% (w/v) trehalose is considered to be most satisfactory, although good data have also been obtained in the presence of 0.01 and 1.0% (w/v) trehalose. The examples given fall into the following groups: protein molecules in the absence of polyethylene glycol (PEG), protein molecules in the presence of PEG (Mr 1000), lipoproteins, lipids and membranes, filaments and tubules, viruses in the absence of PEG, viruses in the presence of PEG, aqueous polymer solutions, and final…