Continuous Synthesis of Inorganic Magnetic Nanocomposites by Laser Pyrolysis for Biomedical Applications

  • PDF / 1,409,021 Bytes
  • 7 Pages / 612 x 792 pts (letter) Page_size
  • 52 Downloads / 210 Views

DOWNLOAD

REPORT


0962-P10-27

Continuous Synthesis of Inorganic Magnetic Nanocomposites by Laser Pyrolysis for Biomedical Applications Sabino Veintemillas Verdaguer1, Brigitte Bouchet-Fabre2, Maria Puerto Morales1, Yann Leconte2, R. Costo1, Pierre Bonville3, and Nathalie C. Herlin-Boime2 1 ICCM, Madrid, 28049, Spain 2 SPAM/LFP (CEA-CNRS URA 2453), gif sur Yvette, 91191, France, Metropolitan 3 SPEC, gif sur Yvette, 91191, France, Metropolitan ABSTRACT : Nanocomposite particles made from encapsulation of magnetic nanoparticles in an inorganic matrix have a real interest in biomedicine due to their high resistance against biodegradation compared with nanoparticles encapsulated in an organic matrix and little work has been published concerning such materials. In this work we use the laser pyrolysis method for the preparation of magnetic composites of Fe-based nanoparticles dispersed in silica and carbon. The precursor is an aerosol of a precursor which can be easily used in a safe way. Important advantages of the laser pyrolysis method are the reproducibility, simplicity (one step method) and continuity which allows producing significant amounts of nanoparticles. The short reaction times (ms) involved in the nucleation of the powders insure the nanometric particle size of both the magnetic component and the inorganic matrix. This paper is focused on the synthesis and characterization of the Fe@SiO2 and Fe@C nanopowders generated by laser pyrolysis of ferrocene diluted in toluene and carried to the reaction zone in aerosol form. The silica coating was formed by the addition of tetraethoxysilane (TEOS) to the reactant. The samples were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), transmission electron microscopy (TEM), specific surface area determination (BET) and magnetic measurements. In the case of Fe@SiO2 the process generates rather homogeneous iron/magnetite particles smaller than 10 nm in diameter surrounded by a SiO2 coating of about 20 nm. In the case Fe@C the process generate iron based magnetic nanoparticles of complex composition smaller than 11 nm surrounded by a graphitic carbon layer of 50 nm. Stable aqueous dispersions at physiological pH were produced for both systems by means of strong oxidation in aqueous solutions, which is a very encouraging result for application in the field of living tissues. INTRODUCTION Biocompatible dispersions of iron based nanoparticles exhibit high magnetic response which make them interesting candidates for of iron nanoparticles have high potential use in applications like contrast agents for magnetic resonance imaging (MRI) or magnetothermia. Additionally, they could be seen as magnetic platforms that after convenient functionalisation could be advantageously used in drug delivery, or biosensor technology. Unfortunately, iron nanoparticles with a large surface area are easily oxidized, i.e. they react vigorously with the oxygen present in the air and also between themselves forming aggregates. In order to decrease reactivity and prevent agglomeration, some studies d