Search results for " MICELLE"
showing 10 items of 179 documents
Morphology of hybrid polystyrene-block-poly(ethylene oxide) micelles: Analytical ultracentrifugation and SANS studies
2006
Abstract Morphology and structure of aqueous block copolymer solutions based on polystyrene- block -poly(ethylene oxide) (PS- b -PEO) of two different compositions, a cationic surfactant, cetyl pyridinium chloride (CPC), and either platinic acid (H 2 PtCl 6 ⋅6H 2 O) or Pt nanoparticles were studied using a combination of analytical ultracentrifugation (AUC), transmission electron microscopy (TEM), and small angle neutron scattering (SANS). These studies combining methods contributing supplemental and analogous structural information allowed us to comprehensively characterize the complex hybrid systems and to discover an isotope effect when H 2 O was replaced with D 2 O. In particular, TEM s…
Antimicrobial Peptides and Their Superior Fluorinated Analogues: Structure-Activity Relationships as Revealed by NMR Spectroscopy and MD Calculations
2010
9 pag., 6 fig, 3 tab.
Volumes and heat capacities of anionic-nonionic surfactant mixtures
1995
Density, heat capacity and surface tension measurements of sodium decylsulfate (NaDeS)-dodecyldimethylamine oxide (DDAO)-water mixtures were carried out as functions of the surfactants total molality mt at fixed stoichiometric mixture compositions XNaDeS. From the surface tension data, the critical micelle concentration of NaDeS-DDAO mixtures as a function of XNaDeS were obtained. From density and heat capacity data, the apparent molar volume VΦ,2 and heat capacity CΦ,2 of NaDeS-DDAO mixtures in water were calculated, respectively. At a given mole fraction, VΦ,2 and CΦ,2 monotonically increases and decreases, respectively, with increasing mt. However, anomalies were observed at XNaDeS=0.1 a…
Demixing of Mixed Micelles. Thermodynamics of Sodium Perfluorooctanoate−Sodium Dodecanoate Mixtures in Water
1997
Conductivity, density, heat capacity, enthalpy of dilution, and osmotic coefficient measurements of water−sodium perfluorooctanoate (NaPFO)−sodium dodecanoate systems were carried out as functions of the surfactants' total molality (mt) at different mole fractions (XNaPFO). From conductivity data, the critical micelle concentration (cmc) and the degree of ionization (β) of the micelles were derived. The cmc's of the micelles are higher than those of the pure surfactants while β depends linearly on XNaPFO. At a given mole fraction, the apparent molar volume (VΦ) and heat capacity (CΦ) of the mixture increases and decreases monotonically with mt, respectively. From data in the premicellar reg…
Thermodynamic Studies of Sodium Dodecyl Sulfate–Sodium Dodecanoate Mixtures in Water
1996
Abstract Conductivity, density, heat capacity, enthalpy of dilution, and osmotic coefficient measurements of water–sodium dodecyl sulfate (NaDS)–sodium dodecanoate systems were carried out as functions of the surfactants total molality ( m t ) at different mole fractions ( X NaDS ). From conductivity data, the critical micelle concentration (cmc) and the degree of ionization of the micelles (β) were calculated. The cmc vs X NaDS profile deviates negatively from that predicted on the basis of the Clint approach, while the β vs X NaDS profile deviates positively from the line correlating the values for pure surfactants. At a given mole fraction, the profiles of all the investigated properties…
Nanohydrogel Formation within the Halloysite Lumen for Triggered and Sustained Release
2018
An easy strategy to obtain nanohydrogels within the halloysite nanotube (HNTs) lumen was investigated. Inorganic reverse micelles based on HNTs and hexadecyltrimethylammonium bromides were dispersed in chloroform, and the hydrophilic cavity was used as a nanoreactor to confine the gel formation based on alginate cross-linked by calcium ions. Spectroscopy and electron microscopy experiments proved the confinement of the polymer into the HNT lumen and the formation of calcium-mediated networks. Biological tests proved the biocompatibility of the hybrid hydrogel. The nanogel in HNTs was suitable for drug loading and sustained release with the opportunity of triggered burst release by chemical …
Galactosylated polymeric carriers for liver targeting of sorafenib
2014
In this paper, we describe the preparation of liver-targeted polymeric micelles potentially able to carry sorafenib to hepatocytes for treatment of hepatocarcinoma (HCC), exploiting the presence of carbohydrate receptors, ASGPR. These micelles were prepared starting from a galactosylated polylactide-polyaminoacid conjugate. This latter was obtained by chemical reaction of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-d,l-aspartamide (PHEA-EDA) with polylactic acid (PLA), and subsequent reaction with lactose, leading to PHEA-EDA-PLA-GAL copolymer. Liver-targeted sorafenib-loaded micelles were obtained in aqueous media at low PHEA-EDA-PLA-GAL copolymer concentration value with nanometer …
About entangled networks of worm-like micelles: a rejected hypothesis
1996
We report new results from small-angle neutron scattering on d(1 2)-cyclohexane/lecithin/water micellar solutions performed as a function of the water content (w(o)), temperature (T) and dispersed phase volume fraction (phi). The data from dilute samples are interpretable in terms of the existence of giant cylindrical reverse micelles and are well fit with a core-shell model (that provides the micelle structure and dimensions) with values of 28 and 45 Angstrom for the inner core and the outer shell radii, almost independent on temperature and concentration. Such a result could appear consistent with the current idea that worm-like micelles are living polymers. On the contrary, the appearanc…
STRATEGIE DI DIREZIONAMENTO ALL’EPATOCARCINOMA DI FARMACI ANTITUMORALI MEDIANTE SISTEMI NANOPARTICELLARI E DI VISUALIZZAZIONE IN CELLULE TUMORALI DEL…
Lo scopo di questo lavoro di tesi è stato quello di realizzare nuovi sistemi nanoparticellari per il direzionamento di farmaci o di agenti per l’imaging, potenzialmente utilizzabili per la terapia e/o per la diagnosi dell’epatocarcinoma (HCC), in particolare per quelle forme caratterizzate dall’overespressione del recettore di membrana degli epatociti ASGP-R o del recettore mitocondriale TSPO. In particolare, nel capitolo 2 sono state descritte la sintesi, la caratterizzazione chimico fisica, la capacità di internalizzazione cellulare e l’efficacia antitumorale di un nuovo sistema nanoparticellare, costituito da un dendrimero a struttura poli-amido-aminica (PAMAM) di quarta generazione, opp…