title: Magnetic heating properties and neutron activation of tungsten-oxide coated biocompatible FePt core-shell nanoparticles.
abstract: Magnetic nanoparticles are highly desirable for biomedical research and treatment of cancer especially when combined with hyperthermia. The efficacy of nanoparticle-based therapies could be improved by generating radioactive nanoparticles with a convenient decay time and which simultaneously have the capability to be used for locally confined heating. The core-shell morphology of such novel nanoparticles presented in this work involves a polysilico-tungstate molecule of the polyoxometalate family as a precursor coating material, which transforms into an amorphous tungsten oxide coating upon annealing of the FePt core-shell nanoparticles. The content of tungsten atoms in the nanoparticle shell is neutron activated using cold neutrons at the Heinz Maier-Leibnitz (FRMII) neutron facility and thereby transformed into the radioisotope W-187. The sizeable natural abundance of 28% for the W-186 precursor isotope, a radiopharmaceutically advantageous gamma-beta ratio of γβ≈30% and a range of approximately 1mm in biological tissue for the 1.3MeV β-radiation are promising features of the nanoparticles' potential for cancer therapy. Moreover, a high temperature annealing treatment enhances the magnetic moment of nanoparticles in such a way that a magnetic heating effect of several degrees Celsius in liquid suspension - a prerequisite for hyperthermia treatment of cancer - was observed. A rise in temperature of approximately 3°C in aqueous suspension is shown for a moderate nanoparticle concentration of 0.5mg/ml after 15min in an 831kHz high-frequency alternating magnetic field of 250Gauss field strength (25mT). The biocompatibility based on a low cytotoxicity in the non-neutron-activated state in combination with the hydrophilic nature of the tungsten oxide shell makes the coated magnetic FePt nanoparticles ideal candidates for advanced radiopharmaceutical applications.
authors.affiliation: Physik Department E21, Technische Universität München, D-85747 Garching, Germany; Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, D-85747 Garching, Germany. Electronic address: Klaus.Seemann@frm2.tum.de.
authors.forename: K M
authors.initials: KM
authors.lastname: Seemann
authors.affiliation: Peter Grünberg Institute (PGI-5) and Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, Research Centre Jülich, D-52425 Jülich, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Luysberg
authors.affiliation: Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, D-85747 Garching, Germany.
authors.forename: Z
authors.initials: Z
authors.lastname: Révay
authors.affiliation: Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, D-85747 Garching, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Kudejova
authors.affiliation: nanoScale Biomagnetics SL, 50012 Zaragoza, Spain.
authors.forename: B
authors.initials: B
authors.lastname: Sanz
authors.affiliation: nanoScale Biomagnetics SL, 50012 Zaragoza, Spain.
authors.forename: N
authors.initials: N
authors.lastname: Cassinelli
authors.affiliation: Experimentalphysik V, Center for Electronic Correlations and Magnetism, Universität Augsburg, D-86159 Augsburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Loidl
authors.affiliation: Klinikum rechts d. Isar, Department of Radiooncology and HMGU München, CCG - Innate Immunity in Tumor Biology", Technische Universität München, D-81675 München, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Ilicic
authors.affiliation: Klinikum rechts d. Isar, Department of Radiooncology and HMGU München, CCG - Innate Immunity in Tumor Biology", Technische Universität München, D-81675 München, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Multhoff
authors.affiliation: Klinikum rechts d. Isar, Department of Radiooncology and HMGU München, CCG - Innate Immunity in Tumor Biology", Technische Universität München, D-81675 München, Germany.
authors.forename: T E
authors.initials: TE
authors.lastname: Schmid
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000187:drug effects; D001672:Biocompatible Materials / Q000737:chemistry* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D006358:Hot Temperature; D007501:Iron / Q000737:chemistry* / Q000494:pharmacology; D060328:Magnetic Phenomena; D053768:Metal Nanoparticles / Q000737:chemistry*; D009502:Neutrons; D010087:Oxides / Q000737:chemistry* / Q000494:pharmacology; D010984:Platinum / Q000737:chemistry* / Q000494:pharmacology; D051381:Rats; D014414:Tungsten / Q000737:chemistry* / Q000494:pharmacology
chemical_list: D001672:Biocompatible Materials; D010087:Oxides; D010984:Platinum; C511604:tungsten oxide; D007501:Iron; D014414:Tungsten
keywords: Core–shell; FePt; Hyperthermia; Nanoparticles; Neutron activation; Polyoxometalates