Berlin 2008 – scientific programme

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MA: Fachverband Magnetismus

MA 16: Magnetic Particles and Clusters I

MA 16.2: Talk

Tuesday, February 26, 2008, 10:45–11:00, H 1028

A fluxgate magnetorelaxometry-based measurement technique for the quality control of magnetic core-shell nanoparticles for applications in medicine and bioanalytics — •Frank Ludwig, Erik Heim, and Meinhard Schilling — TU Braunschweig, Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik, Hans-Sommer-Str. 66, D-38106 Braunschweig

Magnetic nanoparticles (MNPs) find wide application in medicine and bioanalytics. For various applications like MRI-contrast enhancement, magnetofection, drug delivery, hyperthermia, protein and cell separation, as well as immunoassays, the requirements on the particles are quite different. In addition, for in-vivo applications one has to guarantee that the MNPs do not aggregate in the given medium. For applications, such as the magnetic relaxation immunoassay (MARIA), only specific bindings of the functionalized MNPs may occur. Consequently, there is a strong need for a fast, reliable and inexpensive technique for the MNP characterization which is important for both manufacturers and users of core-shell MNPs. We show that the measurement of the magnetorelaxometry (MRX) utilizing a differential fluxgate setup along with the analysis of the MRX curves with the moment superposition model is a quick and powerful tool for the estimation of structure parameters like core and hydrodynamic size distributions as well as anisotropy constant. To verify the estimated size distributions, the results are compared with other measurements, such as TEM and dynamic light scattering. Financial support by the DFG via SFB 578 and the BMBF under contract number 13N9174 is acknowledged.