Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 48: Nanoparticles and Composite Materials II
CPP 48.9: Talk
Friday, March 18, 2011, 12:30–12:45, ZEU 114
Synthesis, characterization, and surface functionalization of gadolinium-based nanoparticles as fluorescent and magnetic probes — •Shih-Hao Kung1, Christina Graf1, Christine Boeglin2, and Eckart Rühl1 — 1Institut für Chemie und Biochemie, Takustr. 3, Freie Universität Berlin, 14195 Berlin, Germany — 2Institute de Physique et Chimie des Materiaux de Strasbourg, 23, rue du Loess, BP43, F-67034 Strasbourg, France
The aim of this work is the investigation of nanoparticles which can be applied as combined fluorescent labels and T1-weighted magnetic resonance imaging (MRI) contrast agents. Gd3+ with its seven unpaired electrons provides the magnetic contrast. Doping the nanoparticles with other rare earth elements, such as europium or erbium, makes the particles fluorescent. The present work is divided into two parts. The first part is a study on the magnetic properties of Gd3+ in the particles as well as changes when the particles are doped with fluorescent Eu3+. This is achieved by X-ray magnetic circular dichroism (XMCD) measurements which were carried out at the Swiss Light Source. In the second part, results on the functionalization of nanoparticles which contain Gd3+ and Er3+ with biocompatible, hydrophilic ligands are presented. Mono- and bivalent polyethylene oxide-phosphonate ligands are prepared and the bond between the ligands and the particles are investigated by infrared spectroscopy. The ligand density is estimated by thermal gravimetric analysis. Moreover, the stability of the ligand-exchanged particles is studied by transmission electron microscopy and dynamic light scattering.