1,720,977 research outputs found
Characterization of spiropyran modified liposomes. Influence of the molecular switch on vesicles stability
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Incorporation of Calix[6]Arene Macrocycles and (Pseudo)Rotaxanes in Bilayer Membranes: Towards Controllable Artificial Liposomal Channels
No full textThe growing interest in the study of membrane-active ion (in particular, anion) transporters motivates the investigation of the mechanisms that underlie the transport process. The interest of the scientific community in this area is largely due to the great importance of transmembrane ion-transport phenomena in many diseases. In this paper we investigated the role of calix[6]arene-based pseudorotaxanes and rotaxanes on transmembrane transport of ions across the bilayer of liposomes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC; diameter 100 nm). We evaluated the effect of these interlocked systems on the properties of the bilayer and on membrane permeability towards chloride ions and 5(6)-carboxyfluorescein. These findings may pave the way for the construction of new generations of pharmacological systems regulating the transport of chloride ions
Light-driven directed proton transport across the liposomal membrane
No full textWe have developed a simple artificial photoresponsive
ion-gating device by inserting molecular switches in
the membrane of liposomes. A controlled and directed proton
transport across the bilayer membrane can lower the internal pH of
the liposomes from neutral to around 4 under combined light and
chemical stimulation
Thermodynamic Analysis of Anion and Cation Effects on the Keto-Enol Equilibrium in Ionic Liquids. A Comparative Study with Conventional Solvents
No full textA comparative thermodynamic investigation of the keto−enol interconversion reaction has been performed in several organic solvents and room-temperature ionic liquids (RTILs) to evaluate the role of the solvent and the effect of the ionic composition of RTILs. The tautomeric constant (KT) values at different temperatures have been analyzed in terms of the van’t Hoff relationship to give the relevant thermodynamic parameters. The ΔG° values are the results of quite different combinations of the ΔH° and ΔS° values depending on the nature of the solvent. As expected, in conventional solvents, the tautomeric equilibrium is enthalpically disfavored and entropically favored
by the increase in solvent polarity. In ionic liquids, the nature of the anion seems to play a primary role in the thermodynamics of the reaction that is endothermic and enthalpically driven in PF6- and TF2N-based RTILs and exothermic but entropically driven in BF4-based RTILs. The cation effect on the thermodynamics of the reaction is more complex and is consistent with a prevalence of the alkyl side chain segregation in the organization of the ILs
Curcumin/Liposome Nanotechnology as Delivery Platform for Anti-inflammatory Activities via NFkB/ERK/pERK Pathway in Human Dental Pulp Treated With 2-HydroxyEthyl MethAcrylate (HEMA)
Get PDFCurcumin, primary component of the spice turmeric extracted from the rhizomes of Curcuma longa, represents the major anti-oxidant and anti-inflammatory substance found in turmeric, acting thought various mechanisms not completely understood. Curcumin modulates cytokines, growth factors, transcription factors, inflammatory molecules and cell signaling pathways. During restorative dentistry practice, free resin monomers of 2-hydroxyethyl methacrylate (HEMA) propagate through dentin micro-channel and pulp into the bloodstream affecting cellular integrity. The study highlights the significance of application of curcumin bioactive component into liposomal formulations (CurLIP) to restore the homeostasis of dental pulp stem cells (hDPSCs) in response to 3 and 5 mmol L-1 HEMA treatment. Cell proliferation in combination with changes of the morphological features, proinflammatory cytokines secretion as Interleukin (IL) 6, IL8, Monocyte Chemoattractant Protein-1 (MCP1) and Interferon-gamma (IFNγ) were assayed along with the nuclear factor (NF)-kB, an inducible transcription factor involved in the activation of several cell processes associated to extracellular signal-regulated kinases (ERK) and posphorylated (p-) ERK pathway. Our results showed a decreased cell proliferation, morphological changes and upregulation of IL6, IL8, MCP1 and IFNγ in presence of 3 and 5 mmol L-1 HEMA treatment. CurLIP therapy in hDPSCs provokes an increase in cell proliferation and the block of inflammatory cytokines secretion through the inhibitory regulation of NFkB/ERK and pERK signaling cascade. The natural nanocarrier CurLIP influences numerous biochemical and molecular cascades causing anti-inflammatory properties in response to HEMA treatment in human dental pulp stem cells, representing an innovative endodontic formulation able to improve the quality of dental care with a major human community impact
Embedding calix[4]resorcinarenes in liposomes: Experimental and computational investigation of the effect of resorcinarene inclusion on liposome properties and stability
Get PDFTwo calix[4]resorcinarenes, which differ in the length of the alkyl chain on the methylene bridge between the aromatic rings, have been embedded in unilamellar liposomes prepared from 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphocholine in three host/guest ratios, following two different procedures. The effect of the insertion of the guests has been evaluated through the measurements of the viscosity and the kinetic stability of the liposomal systems by means of the fluorescent probes pyrene and 5(6)-carboxyfluorescein. The presence of the guests reduces the viscosity of the liposomes, suggesting a modification of the bilayer structure. However, this does not affect liposome stability. A calix[4]resorcinarene cavitand with a more rigid conformation compared to the parent resorcinarene, has been also synthetized and embedded in liposomes. The free energy of the insertion of the substrates in the lipid bilayer has been evaluated through Molecular Dynamics simulations.© 2019 Elsevier B.V
Optimizing the interactions of surfactants with graphitic surfaces and clathrate hydrates
Get PDFSurfactants are amphiphilic molecules active at the surface/interface and able to self-assemble. Due to these properties surfactants have been extensively used as detergents, emulsifiers, foaming agents or wetting agents. New perspectives have been opened by the exploitation of surfactants for their capacity to interact as well with simple molecules or surfaces. This feature article gives an overview on significant contributions in the panorama of the current research on surfactants, partly accomplished as well by our group of research. We look at several recent applications, i.e. adsorption to graphitic surfaces and interactions with hydrate crystals, with the eye of physical organic chemists. We demonstrate that, from the detailed investigation of the forces involved in the interactions with hydrophobic surfaces, it is possible to optimize the design of the surfactant able to form a stable and unbundled carbon nanotube dispersion as well as the best exfoliating agent for graphitic surfaces. By studying the effect of different surfactants on the capacity to favor or disfavor the formation of gas hydrate, it is possible to highlight the main features that a surfactant should possess in order to be devoted to that specific application
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