Search results for "Amphiphile"
showing 10 items of 270 documents
Synthesis of a Fullerene[60] Cryptate and Systematic Langmuir-Blodgett and Thin-Film Investigations of Amphiphilic Fullerene Derivatives
1995
The synthesis of the first fullerene cryptate 7 with a sodium ion bound to a benzo[2.2.2]cryptand covalently attached to a methanofullerene[60] is described. The amphiphilic properties of 7 as well as of a variety of other covalent fullerene derivatives with polar functional groups and the ability of these compounds to form Langmuir monolayers at the air-water interface were investigated in a systematic study. Among these derivatives are Diels-Alder adducts of C60 and methanofullerenes, four of which are fullerene C-glycosides. The films at the water surface were characterized by their surface pressure versus molecular area isotherms, compression and expansion cycles, and optical light micr…
New amphiphilic terphenyl liquid crystals for the preparation of highly ordered ultrathin films
1991
Four new amphiphilic liquid crystals have been synthesized, in which terphenyl was used as the mesogenic unit. In order to enable the formation of Langmuir Monolayers at the air/water-interface, the molecules were equipped with slightly polar headgroups such as esters or a carboxylic acid group. All compounds can be transferred onto solid substrates. In addition, it is possible to prepare freely suspended films of at least one compound in the temperature range of the smectic phases. The phases of the different states, bulk, monolayer, freely suspended film, and Langmuir-Blodgett multilayers have been investigated by means of monolayer isotherms, optical textures, differential scanning calor…
Studies of Preparation and Stability of Liposomes Formed by 1,1'-[(3,5-didodeciloxycarbonyl-4-phenyl-1,4-dihydropyridine-2,6-diil)-dimethylen]Bispyri…
2013
In this work we describe the studies of preparation and stability of liposomes formed by 1,1'-[(3,5-didodeciloxycarbonyl-4-phenyl-1,4-dihydropyridine-2,6-diil) dimethylebispyridinium dibromide, novel lipid-like compound. The influence of the amount of amphiphilic compound, solvent and sonication time was studied. Liposomes were prepared by dispersing of compound in the corresponding media at a selected concentration by sonication using a probe type sonicator and characterised by atomic force microscopy (AFM) and dynamic light scattering (DLS) methods.
Geometric and thermodynamic considerations about the lipid vesicles formation in water (I. Unilamellar vesicles)
2001
Abstract A parametrization based on the differential geometry and on the thermodynamics of dispersed systems has been developed in order to explain the processes leading to the formation of lipid vesicles in water. Several factors of known importance such as aqueous interlayer, chain-length, lipid chain-packing and membrane asymmetry, as well as the existence of two different surfaces in the vesicular bilayer have been considered. The barrier which amphiphile molecules need to surpass in order to the vesicle be formed has three contributions related to the surface energy, the mechanical energy due to overpressure and the excess of chemical potential. The theoretical results define the condi…
Probing the self-assembly and stability of oligohistidine based rod-like micelles by aggregation induced luminescence.
2016
OA hybrid The synthesis and self-assembly of a new C2-symmetric oligohistidine amphiphile equipped with an aggregation induced emission luminophore is reported. We observe the formation of highly stable and ordered rod-like micelles in phosphate buffered saline, with a critical aggregation concentration below 200 nM. Aggregation induced emission of the luminophore confirms the high stability of the anisotropic assemblies in serum.
NEW SELF-ASSEMBLING POLYASPARTYLHYDRAZIDE COPOLYMER MICELLES FOR ANTICANCER DRUG DELIVERY.
2010
A new amphiphilic copolymer have been synthesized starting from the hydrosoluble polyaspartylhydrazide (PAHy) polymer, by grafting both hydrophilic PEG(2000) chains and hydrophobic palmitic acid (C(16)) moieties on polymer backbone, and the structure of obtained PAHy-PEG(2000)-C(16) copolymer have been characterized by 2D (1)H/(13)C NMR experiments. PAHy-PEG(2000)-C(16) copolymer showed the ability of self-assembling in aqueous media giving a core-shell structure and resulted potentially useful for encapsulating and dissolving hydrophobic drug. The formation of micellar core-shell structure has been investigated by 2D (1)H NMR NOESY experiments. The presence of cross-peaks for protons of C(…
SELF-ASSEMBLED AMPHIPHILIC HYALURONIC ACID GRAFT COPOLYMERS FOR TARGETED RELEASE OF ANTITUMORAL DRUG
2009
Polymeric micelles obtained by self-assembling of amphiphilic hyaluronic acid (HA) graft copolymers have been prepared and characterized. In particular, hyaluronic acid (HA) has been grafted to polylactic acid (PLA) and polyethylenglycol chains (PEG), then the copolymers able to form micelles in aqueous medium have been chosen to entrap the antitumoral drug Doxorubicin. The critical aggregation concentration of HA-g-PLA or HA-g-PLA-g-PEG micelles has been determined by using pyrene as a fluorescent probe, whereas their shape and size have been evaluated by light scattering measurements, scanning and transmission electron microscopies. The selective cytotoxicity of drug loaded micelles towar…
Fate of Linear and Branched Polyether-Lipids In Vivo in Comparison to Their Liposomal Formulations by 18F-Radiolabeling and Positron Emission Tomogra…
2015
In this study, linear poly(ethylene glycol) (PEG) and novel linear-hyperbranched, amphiphilic polyglycerol (hbPG) polymers with cholesterol (Ch) as a lipid anchor moiety were radiolabeled with fluorine-18 via copper-catalyzed click chemistry. In vivo investigations via positron emission tomography (PET) and ex vivo biodistribution in mice were conducted. A systematic comparison to the liposomal formulations with and without the polymers with respect to their initial pharmacokinetic properties during the first hour was carried out, revealing remarkable differences. Additionally, cholesterol was directly labeled with fluorine-18 and examined likewise. Both polymers, Ch-PEG27-CH2-triazole-TEG-…
Hyaluronic Acid-Based Micelles as Ocular Platform to Modulate the Loading, Release, and Corneal Permeation of Corticosteroids
2017
The aim of this work is to prepare hyaluronic acid-based micelles as a platform to load corticosteroid drugs and to improve their corneal permeation after administration on the ocular surface. Three amphiphilic derivatives of hyaluronic acid (HA) are synthesized using different amounts of hexadecylamine (C16 -NH2 ). HAC16 a, HAC16 b, and HAC16 c derivatives are able to form micelles by the cosolvent evaporation method and to entrap corticosteroids (dexamethasone, triamcinolone, triamcinolone acetonide). HAC16 a and HAC16 b micelles show the best results in terms of drug loading and particle size. They are also able to improve drug release compared to free drug solution or suspension. In add…
In Silico Design Enables the Rapid Production of Surface-Active Colloidal Amphiphiles
2020
A new technology platform built on the integration of theory and experiments to enable the design of Janus colloids with precision control of surface anisotropy and amphiphilicity could lead to a disruptive transformation in the next generation of surfactants, photonic or phononic materials, and coatings. Here, we exploit molecular dynamics (MD) simulations to guide the rational design of amphiphilic polymer Janus colloids by Flash NanoPrecipitation (FNP), a method capable of the production of colloids with complex structure without the compromise of reduced scalability. Aided by in silico design, we show in experiments that amphiphilic Janus colloids can be produced using a unique blend of…