Search results for "Colloid"

Synthesis and noncovalent protein conjugation of linear-hyperbranched PEG-poly(glycerol) alpha,omega(n)-telechelics.

2009

Linear-hyperbranched, heterobifunctional alpha,omega(n) telechelic block copolymers consisting of a linear poly(ethylene glycol) (PEG) chain and a hyperbranched polyglycerol (PG) block have been prepared in five steps, using a protected amino-functional initiator. The polyfunctionality omega(n) (OH groups) can be adjusted by the degree of polymerization (DP(n)) of the polyglycerol block. Subsequent introduction of a single biotin unit by amidation in alpha-position permitted noncovalent bioconjugation with avidin.

Inhalable polymer-glycerosomes as safe and effective carriers for rifampicin delivery to the lungs

2016

Rifampicin loaded glycerosomes, vesicles composed of phospholipids, glycerol and water, were combined with trimethyl chitosan chloride (TMC) to prepare TMC-glycerosomes or, alternatively, with sodium hyaluronate (HY) to obtain HY-glycerosomes. These new hybrid nanovesicles were tested as carriers for pulmonary delivery of rifampicin. Glycerosomes without polymers were also prepared and characterized. All vesicles were similar: they were spherical, multilamellar and able to incorporate good amount of rifampicin (EE%∼55%). The addition of the polymers to the formulations allowed an increase of mean diameter. All the glycerosomes, in particular HY-glycerosomes, were able to deliver the drug to…

Gold Nanoparticles Coated with a Thermosensitive Hyperbranched Polyelectrolyte: Towards Smart Temperature and pH Nanosensors

2008

Wetting properties at the surface of iota-carrageenan-based edible films

2006

International audience; Surface properties of edible films composed of a polymeric matrix of carrageenan in association with hydrophobic material were studied by contact angle measurements. The use of this technique not only in a static mode but also in a dynamic way enables investigation of surface hydrophobicity as well as surface wettability. The absorption flux inside the material can be estimated from the wetting kinetic, which can be very useful to quickly compare water barrier efficiency of the tested films. Comparison of carrageenan films with films containing known amounts of additives enables understanding and correlation of changes of the surface properties with the nature of use…

Hydrogels containing 5-Fluorouracil obtained by γ-irradiation. Synthesis, characterization and in vitro release studies

2001

The functionalization of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) with glycidyl methacrylate (GMA) gives rise to a water-soluble copolymer PHEA-GMA (PHG) containing double bonds and ester groups in the side chain. Aqueous solutions of PHG alone or in combination with N,N′ methylenbisacrylamide (BIS) have been exposed to a γ-ray source at different irradiation doses in order to obtain polymeric networks. All samples have been prepared both as water-swellable microparticles and as gel systems. Microparticles have been characterized by FT-IR spectrophotometry and swelling measurements in aqueous media mimicking biological fluids. The effect of irradiation dose and BIS presence on rheol…

New biodegradable hydrogels based on a photo-cross-linkable polyaspartamide and poly(ethylene glycol) derivatives. Release studies of an anticancer d…

2001

The functionalization of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) with glycidyl methacrylate (GMA) gives rise to a water-soluble photosensitive copolymer PHEA-GMA (PHG). Aqueous solutions of PHG alone or in combination with various concentrations of poly(ethylene glycol) dimethacrylate or poly(ethylene glycol) diacrylate (PEGDA) have been exposed to a source of UV rays at 313 nm in order to obtain polymeric networks. All samples have been prepared both as water-swellable microparticles and as gel systems. Microparticles have been characterised by Fourier transform IR spectrophotometry, dimensional analysis and swelling measurements in aqueous media mimicking biological fluids. In vi…

In syringe hybrid monoliths modified with gold nanoparticles for selective extraction of glutathione in biological fluids prior to its determination …

2020

Abstract In this work, a simple device for extraction glutathione (GSH) in biological fluids using a hybrid monolithic material within a polypropylene syringe is developed. For this purpose, glycidyl methacrylate-based monolith was firstly prepared within this housing material, and the polymer was modified with different ligands (ammonia, cysteamine and cystamine). The resulting materials (containing amine or thiol groups, respectively) were then functionalized with gold nanoparticles (AuNPs). The hybrid material that gave the largest AuNPs coverage was selected as solid-phase (SPE) sorbent and several variables affecting the extraction recovery of this compound were investigated. Under opt…

Preparation and cytotoxic properties of goethite-based nanoparticles covered with decyldimethyl(dimethylaminoethoxy) silane methiodide

2010

The present work describes the synthesis, physico-chemical and biological properties of the first water-soluble goethite nanoparticles covered with biologically active components: oleic acid and cytotoxic decyldimethyl(dimethylaminoethoxy)silane methiodide. The structure of initial goethite nanoparticles synthesized was proved by XRD analysis and the rough estimation of nanoparticles core size gave the value of 8 nm. The size of colloidal water-soluble nanoparticles, determined by dynamic light scattering, was within 19–35 nm. Magnetic properties and cytotoxicity (against HT-1080 and MG-22A tumor cell lines) of the nanoparticles obtained were investigated. Copyright © 2009 John Wiley & Sons…

Exploiting multivalent nanoparticles for the supramolecular functionalization of graphene with a nonplanar recognition motif.

2013

The supramolecular modification of planar graphene with the geometri- cally mismatched, curved 9,10-di(1,3-dithiole-2-ylidene)-9,10-dihydroanthracene (exTTF) molecule is demonstrated. The exTTF-graphene interaction is governed by p-p and CH-p interactions, with a negligible contribution from charge transfer. We amplified these weak forces through multivalent gold nanoparticles. Our re- sults show that planarity is not a prerequisite for recognition motifs for graphene.

GFP-mut2 Proteins in Trehalose-Water Matrixes: Spatially Heterogeneous Protein-Water-Sugar Structures

2007

We report investigations on the properties of nanoenvironments around single-GFP-mut2 proteins in trehalose-water matrixes. Single-GFPmut2 molecules embedded in thin trehalose-water films were characterized in terms of their fluorescence brightness, bleaching dynamics, excited state lifetime, and fluorescence polarization. For each property, sets of approximately 100-150 single molecules have been investigated as a function of trehalose content and hydration. Three distinct and interconverting families of proteins have been found which differ widely in terms of bleaching dynamics, brightness, and fluorescence polarization, whose relative populations sizably depend on sample hydration. The r…