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Rodrigues A.R.O.,University of Minho | Ramos J.M.F.,University of Minho | Gomes I.T.,University of Minho | Gomes I.T.,IFIMUP IN Institute Nanociencia e Nanotecnologia | And 5 more authors.
RSC Advances | Year: 2016

Manganese ferrite nanoparticles with a size distribution of 26 ± 7 nm (from TEM measurements) were synthesized by the coprecipitation method. The obtained nanoparticles exhibit a superparamagnetic behaviour at room temperature with a magnetic squareness of 0.016 and a coercivity field of 6.3 Oe. These nanoparticles were either entrapped in liposomes (aqueous magnetoliposomes, AMLs) or covered with a lipid bilayer, forming solid magnetoliposomes (SMLs). Both types of magnetoliposomes, exhibiting sizes below or around 150 nm, were found to be suitable for biomedical applications. Membrane fusion between magnetoliposomes (both AMLS and SMLs) and GUVs (giant unilamellar vesicles), the latter used as models of cell membranes, was confirmed by Förster Resonance Energy Transfer (FRET) assays, using a NBD labeled lipid as the energy donor and Nile Red or rhodamine B-DOPE as the energy acceptor. A potential antitumor thienopyridine derivative was successfully incorporated into both aqueous and solid magnetoliposomes, pointing to a promising application of these systems in oncological therapy, simultaneously as hyperthermia agents and nanocarriers for antitumor drugs. © The Royal Society of Chemistry 2016.

Gomes I.T.,University of Minho | Gomes I.T.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Almeida B.G.,University of Minho | Araujo J.P.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Araujo J.P.,University of Porto
EPJ Web of Conferences | Year: 2013

Thin films of Pr0.5Ca0.5MnO3 have been deposited on z-cut LiNbO3 by pulsed laser ablation. The Xray diffraction measurements showed that the films have grown highly oriented on LiNbO3, with a pseudocubic (111) preferred growth direction. The thicknesses of the films, measured by low angle X-ray reflectivity, are between 13 and 140 nm. Their electrical resistivity present a semiconducting-like behaviour with an anomaly around 240 K, that corresponds to the charge ordering transition. The temperature of the transition (TCO) was estimated from ln ρ vs. (1/T) plots. The charge ordering temperature was found to be dependent on the strain induced by the lattice mismatch on the films. © 2013 Owned by the authors, published by EDP Sciences.

Custodio L.M.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Sousa C.T.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Ventura J.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Teixeira J.M.,IFIMUP IN Institute Nanociencia e Nanotecnologia | And 4 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The Bruggeman effective medium is used to study the transition to hyperbolic dispersion of visible light in thin-film metal-dielectric composite metamaterial of varying mixing proportion. This transition is experimentally demonstrated by the detection of the swap between the refracted birefringence components in fabricated composites of silver nanowires embedded in anodic aluminium oxide. Three refraction regimes are observed in a single composite using excitation radiation on both sides of the transition. © 2012 American Physical Society.

Rodrigues A.R.O.,University of Minho | Gomes I.T.,University of Minho | Gomes I.T.,IFIMUP IN Institute Nanociencia e Nanotecnologia | Almeida B.G.,University of Minho | And 3 more authors.
Physical Chemistry Chemical Physics | Year: 2015

Nickel ferrite nanoparticles with superparamagnetic behavior at room temperature were synthesized using a coprecipitation method. These magnetic nanoparticles were either covered with a lipid bilayer, forming dry magnetic liposomes (DMLs), or entrapped in liposomes, originating aqueous magnetoliposomes (AMLs). A new and promising method for the synthesis of DMLs is described. The presence of the lipid bilayer in DMLs was confirmed by FRET (Förster Resonance Energy Transfer) measurements between the fluorescent-labeled lipids NBD-C12-HPC (NBD acting as a donor) included in the second lipid layer and rhodamine B-DOPE (acceptor) in the first lipid layer. An average donor-acceptor distance of 3 nm was estimated. Assays of the non-specific interactions of magnetoliposomes with biological membranes (modeled using giant unilamellar vesicles, GUVs) were performed. Membrane fusion between both aqueous and dry magnetoliposomes and GUVs was confirmed by FRET, which is an important result regarding applications of these systems both as hyperthermia agents and antitumor drug nanocarriers. © the Owner Societies 2015.

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