Design of parenteral MNP-loaded PLGA nanoparticles by a low-energy emulsification approach as theragnostic platforms for intravenous or intratumoral administration

Encapsulation of magnetic nanoparticles (MNP) into PLGA nanoparticles has been achieved by nano-emulsion templating using for the first time both, a low-energy emulsification method as well as biocompatible components accepted for pharmaceuticals intended for human use. The incorporation of MNP by nano-emulsion templating method proposed in this work has been investigated in two different systems applying mild process conditions and is shown to be simple and versatile, providing stable MNP-loaded PLGA nanoparticles with tunable size and MNP concentration. MNP-loaded PLGA nanoparticles showed sizes below 200nm by DLS and 50nm by TEM, and mean MNP loading per PLGA nanoparticle of 1 to 4, depending on the nanoparticle dispersion composition. Physical-chemical features suggest that the MNP-loaded PLGA nanoparticles obtained are good candidates for intravenous or intratumoral administration.Financial support from MINECO (grant CTQ2014-52687-C3-1-P); Generalitat de Catalunya (grant 2014-SGR-1655), and CIBER-BBN are acknowledged. CIBER-BBN is an initiative funded by the VI National R&D&I Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. Cristina Fornaguera is grateful to AGAUR for their Predoctoral Fellowship (grant FI-DGR 2012).Peer reviewe

Liquid crystalline magnetic materials

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In situ synthesis of cobalt nanoparticles in functionalized liquid crystalline polymers

Magnetic hybrid liquid crystal composites have been obtained by thermal decomposition of a cobalt coordination precursor in the presence of a liquid crystal polymer and functional molecules (acid or amine) interacting with the precursor. The final materials contain anisotropic and/or spherical nanoparticles depending on the reaction conditions. They are all mesomorphous and ferromagnetic at ambient temperature. The role of the macromolecular chains as stabilizers of the nanoparticles has been examined. Apart from stabilizing, the polymer chains also prevent the easy access of the functional molecules to the surface of the nanoparticles, necessary to obtain anisotropic objects. Last but not least, the ferromagnetic behavior of the nanoobjects is shown to be enhanced by the presence of the liquid crystal phase: the nano-objects easily align by application of a 3 T magnetic field

In situ synthesis of cobalt nanoparticles in functionalized liquid crystalline polymers

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Liquid Crystalline Polymers as Tools for the Formation of Nanohybrids

International audienceThis chapter reviews the results obtained for the use of liquid crystalline polymers for the stabilization or the in situ synthesis of nanoparticles. It aims at giving the reader an insight into incorporating different types of nanoparticles, e.g. metallic or metal oxides, in various types of liquid crystalline polymers. In particular, this review highlights the importance of the nanoparticles-liquid crystalline polymers interaction in order to access new materials exhibiting synergetic properties. Of special interest is the case of liquid crystalline materials embedding magnetic or photoluminescent nanoparticles

Carbon Coating, Carburization and High Temperature Stability Improvement of Cobalt Nanorods

International audienceThe reactivity of highly crystalline hcp cobalt nanorods (NRs) with organic solvents at high temperature was studied. Cobalt NRs with a mean diameter of 15 nm were first synthesized by the polyol process and then heated at 300 °C in octadecene (ODE), oleylamine (OA) or mixtures of these two solvents. The surface and structural modifications of the Co NRs were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning and transmission electron microscopy (SEM and TEM). A disordered carbon shell was formed at the cobalt rod surface, the thickness of which can be tuned from 5 to 25 nm by increasing the amount of oleylamine in the solvent mixture. This carbon shell partially reduced the native cobalt oxide observed at the surface of the NRs and drastically improved their temperature stability as inferred from in-situ XRD study and TEM. The shape anisotropy and the crystallite anisotropy of the hcp phase are both preserved up to 400 °C for the carbon coated cobalt rods whereas the uncoated NRs lose their anisotropy at 225 °C. Treatments at 300 °C in ODE/OA mixtures for different durations allowed the progressive carburization of Co to Co2C. The crystallographic orientation of the Co2C grains within the cobalt NRs combined with the different carbon shell thickness on the {10-10} and (0001) facets of the rods suggested a preferential carburization from the lateral facets of the hcp cobalt rods