Search results for "hydrophilic"

showing 10 items of 276 documents

Size influences the effect of hydrophobic nanoparticles on lung surfactant model systems

2013

Item does not contain fulltext The alveolar lung surfactant (LS) is a complex lipid protein mixture that forms an interfacial monolayer reducing the surface tension to near zero values and thus preventing the lungs from collapse. Due to the expanding field of nanotechnology and the corresponding unavoidable exposure of human beings from the air, it is crucial to study the potential effects of nanoparticles (NPs) on the structural organization of the lung surfactant system. In the present study, we investigated both, the domain structure in pure DPPC monolayers as well as in lung surfactant model systems. In the pure lipid system we found that two different sized hydrophobic polymeric nanopa…

Systems BiophysicsPhase transitionPulmonary Surfactant-Associated ProteinsMaterials science12-DipalmitoylphosphatidylcholineSwineVesicleBiophysicstechnology industry and agricultureNanoparticleMembranes ArtificialNanotechnologyBiological membraneModels BiologicalPhase TransitionSurface tensionPulmonary surfactantChemical engineeringPhase (matter)MonolayerAnimalsNanoparticlesHydrophobic and Hydrophilic InteractionsNanomedicine Radboud Institute for Molecular Life Sciences [Radboudumc 19]
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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Characterization of Hydrophilic Gold(I) N-Heterocyclic Carbene (NHC) Complexes as Potent TrxR Inhibitors Using Biochemical and Mass Spectrometric App…

2017

We report here on the synthesis of a series of mono-and dinuclear gold(I) complexes exhibiting sulfonated bis(NHC) ligands and novel hydroxylated mono(NHC) Au(I) compounds, which were also examined for their 'biological activities. Initial cell viability assays show strong antiproliferative activities of the hydroxylated mono(NHC) gold compounds (8 > 9 > 10) against 2008 human ovarian cancer cells even after 1 h incubation. In order to gain insight into the mechanism of biological action of the gold compounds, their effect on the pivotal cellular target seleno-enzyme thioredoxin reductase (TrxR), involved in the maintenance of intracellular redox balance, was investigated in depth. Th…

Thioredoxin Reductase 1AuranofinSilverStereochemistryThioredoxin reductaseThioredoxin Reductase 2WATER-SOLUBLE RUTHENIUM(II)Antineoplastic Agents010402 general chemistryG-quadruplexLigandsIN-VITRO CYTOTOXICITYLIGANDS SYNTHESIS01 natural sciencesInorganic Chemistrychemistry.chemical_compoundDrug StabilityThioredoxin Reductase 1Coordination ComplexesTHIOREDOXIN REDUCTASE INHIBITIONCell Line TumormedicineOrganogold CompoundsAnimalsHumansCRYSTAL-STRUCTURESPhysical and Theoretical ChemistryCANCER CELLSBIOLOGICAL-PROPERTIES010405 organic chemistryChemistryMOLECULAR-MECHANISMSDNA0104 chemical sciencesRatsG-QuadruplexesGlutathione ReductaseSolubilityBiological targetCancer cellPLATINUM ANTICANCER DRUGSMETAL-COMPLEXESGoldReactive Oxygen SpeciesCarbeneHydrophobic and Hydrophilic InteractionsOrganogold Compoundsmedicine.drugInorganic Chemistry
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PHEA-graft-polybutylmethacrylate copolymer microparticles for delivery of hydrophobic drugs.

2012

Abstract Polymeric microparticles encapsulating two model hydrophobic drugs, beclomethasone dipropionate (BDP) and flutamide (FLU) were prepared by using the high pressure homogenization-solvent evaporation method starting from a oil-in-water emulsion. For the preparation of polymeric microparticles a α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) graft copolymer with comb like structure was properly synthesized via grafting from atom transfer radical polymerization (ATRP) technique, by using two subsequent synthetic steps. In the first step a polymeric multifunctional macroinitiator was obtained by the conjugation of a proper number of 2-bromoisobutyryl bromide (BIB) residues to the…

Time FactorsBioadhesivePharmaceutical ScienceCell LineDrug Delivery SystemsPolymethacrylic AcidsPolymer chemistryMucoadhesionCopolymerSide chainHumansPhea polybutylmethacrylate microparticles drug deliveryParticle SizeGlucocorticoidsDrug CarriersDose-Response Relationship DrugChemistryAtom-transfer radical-polymerizationBeclomethasoneAdhesivenessAndrogen AntagonistsGraftingFlutamideMicrospheresPolymerizationDelayed-Action PreparationsEmulsionSolventsNanoparticlesEmulsionsCaco-2 CellsPeptidesHydrophobic and Hydrophilic InteractionsInternational journal of pharmaceutics
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Synthesis of Mesoporous Supraparticles on Superamphiphobic Surfaces

2015

A method for mesoporous supraparticle synthesis on superamphiphobic surfaces is designed. Therefore, supraparticles assembled with nanoparticles are synthesized by the evaporation of nanoparticle dispersion drops on the superamphiphobic surface. For synthesis, no further purification is required and no organic solvents are wasted. Moreover, by changing the conditions such as drop size and concentration, supraparticles of different sizes, compositions, and architectures are fabricated.

TitaniumMaterials scienceDrop sizeSurface PropertiesMechanical EngineeringMetal NanoparticlesTin CompoundsWaterNanoparticlechemistry.chemical_elementNanoparticle dispersionEvaporation (deposition)Chemical engineeringchemistryMechanics of MaterialsMicroscopy Electron ScanningGeneral Materials SciencePorosityMesoporous materialMetal nanoparticlesHydrophobic and Hydrophilic InteractionsPorosityTitanium
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Refractive index and equilibrium water content of conventional and silicone hydrogel contact lenses

2006

Prova tipográfica (In Press)

Traditional handheld refractometerMaterials scienceSiliconesRefractive index02 engineering and technologyRefraction Ocular03 medical and health scienceschemistry.chemical_compound0302 clinical medicineOpticsSiliconeRefractometerHumanssilicone hydrogelCLR 12-70Siloxane hydrogelScience & TechnologyEquilibrium water contentbusiness.industryWaterHydrogelsHEMAEquipment DesignContact Lenses Hydrophilic021001 nanoscience & nanotechnologyAtago N-2ESensory SystemsContact lensOphthalmologyRefractometrysoft contact lenschemistrySiloxaneSelf-healing hydrogels030221 ophthalmology & optometry0210 nano-technologybusinessRefractive indexRefractometryconventional hydrogelOptometryBiomedical engineering
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Lipid phase transition in saccharide-coated cholate-containing liposomes: coupling to the surrounding matrix.

2005

We performed FTIR measurements on cholate-containing liposomes (CCL) embedded in saccharide (trehalose or sucrose) matrixes with different contents of residual water. We obtained information on the CCL phase transition following the thermal evolution (310-70 K) of the IR spectrum of the carbonyl moieties of phospholipids in the frequency range 4225-4550 cm(-1). Furthermore, we simultaneously followed the thermal evolution of the water association band, which gave information on the behavior of the surrounding water-saccharide matrix. The analysis revealed a small sub-band of the water association band present in CCL but not in cholate-free liposomes, the thermal evolution of which is tightl…

Trehalose Liposomes Thermal behaviourSucroseSucroseSurface PropertiesLipid BilayersPhospholipidInfrared spectroscopydigestive systemPermeabilityPhase Transitionchemistry.chemical_compoundDrug Delivery Systemsstomatognathic systemHydrophilySpectroscopy Fourier Transform InfraredElectrochemistryGeneral Materials ScienceLipid bilayer phase behaviorFourier transform infrared spectroscopySpectroscopyPhospholipidsLiposomeChromatographydigestive oral and skin physiologyTemperatureTrehaloseWaterSurfaces and InterfacesCondensed Matter PhysicsTrehaloseSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)chemistryLiposomesCholatesHydrophobic and Hydrophilic InteractionsLangmuir : the ACS journal of surfaces and colloids
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Rapid determination of sterols in vegetable oils by CEC using methacrylate ester-based monolithic columns

2008

A method for the determination of sterols in vegetable oils by CEC with UV-Vis detection, using methacrylate ester-based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4-butanediol (12 wt% 1,4-butanediol in the polymeriz…

TrisDetection limitgeographygeography.geographical_feature_categoryChromatographyResolution (mass spectrometry)ChemistryClinical BiochemistryPhytosterolsReproducibility of ResultsMethacrylateSensitivity and SpecificityBiochemistryAnalytical ChemistrySolventchemistry.chemical_compoundMonomerPolymethacrylic AcidsPolymerizationCapillary ElectrochromatographyMethacrylatesPlant OilsMonolithHydrophobic and Hydrophilic InteractionsFood AnalysisELECTROPHORESIS
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Multivariate optimization of the hollow fibre liquid phase microextraction of muscimol in human urine samples.

2016

Abstract A liquid phase microextraction based on hollow fibre followed by liquid chromatographic determination was developed for the extraction and quantitation of the hallucinogenic muscimol from urine samples. Method applicability on polar hallucinogens was also tested on two alkaloids, a psychedelic hallucinogen, tryptamine and a polar amino acid, tryptophan which exists in its charged state in the entire pH range. A multivariate design of experiments was used in which a half fractional factorial approach was applied to screen six factors (donor phase pH, acceptor phase HCl concentration, carrier composition, stirring rate, extraction time and salt content) for their extent of vitality i…

TryptamineMaleAnalyteCentral composite designCalibration curveLiquid Phase MicroextractionClinical BiochemistryAnalytical chemistry010402 general chemistry01 natural sciencesBiochemistryAnalytical ChemistryMatrix (chemical analysis)chemistry.chemical_compoundYoung AdultLimit of DetectionHumansDetection limitAnalysis of VarianceChromatographyChemistryMuscimolHydrophilic interaction chromatography010401 analytical chemistryExtraction (chemistry)TryptophanReproducibility of ResultsCell BiologyGeneral MedicineModels TheoreticalReference StandardsTryptamines0104 chemical sciencesCalibrationMultivariate AnalysisJournal of chromatography. B, Analytical technologies in the biomedical and life sciences
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Comparative Study of Different Column Types for the Separation of Polar Basic Hallucinogenic Alkaloids

2016

The number of hallucinogenic compounds that have been separated simultaneously by liquid chromatography is limited. This research aimed to identify a column(s) that can allow for separation of several hallucinogens. The extent of separation of seven polar hallucinogenic tryptamine and phenethylamine derived alkaloids containing a basic N atom that becomes protonated at low pH values were investigated on five reverse-based columns and one hydrophilic interaction liquid chromatography (HILIC) column. An RP-phenyl and a negatively charged fused core HILIC were identified and recommended as effective columns in this regard. This research is the first to introduce a HILIC column in separation of…

TryptaminePhenethylaminePolarity (physics)01 natural sciencesDiluenttetrahydrofuranchemistry.chemical_compoundmedicinehallucinogenOrganic chemistrypolar compoundsHILICAcetonitrilepsilocinTetrahydrofuranChromatography010405 organic chemistryHydrophilic interaction chromatography010401 analytical chemistryGeneral Chemistrymuscimol0104 chemical scienceschemistryPsilocinHallucinogenmedicine.drugSouth African Journal of Chemistry = Suid-Afrikaanse Tydskrif Vir Chemie
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