Regensburg 2013 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 7: Magnetic Particles in Biomedical Diagnostics and Therapy (jointly with BP,CPP,ST)

MA 7.3: Vortrag

Montag, 11. März 2013, 10:30–10:45, H22

Realization of homogeneous bioassays using magnetic nanoparticles in time-varying magnetic fields — •Frank Ludwig, Thilo Wawrzik, Jan Dieckhoff, and Meinhard Schilling — TU Braunschweig, Institut für Elektrische Messtechnik und Grundlagen der Elektrotechnik, Hans-Sommer-Str. 66, D-38106 Braunschweig

Homogeneous bioassays utilizing functionalized magnetic nanoparticles (MNP) are based on the MNP’s dynamics in time-varying magnetic fields which differs for bound and unbound markers. For this the dynamics of unbound markers must be dominated by the Brownian mechanism whereas bound ones relax either via the Brownian mechanism with an increased time constant or via the Néel mechanism. In our group, the following principal approaches for the realization of homogeneous bioassays with MNP are pursued: With our fluxgate magnetorelaxometry (MRX) setup, the dynamics is studied in the time domain and time constants between about 400 µs and a few s are accessible. With our ac susceptibility (ACS) systems, the dynamics is studied in the frequency domain for excitation field frequencies between a few tens of Hz and 1 MHz. Similarly to the ACS technique, the MNP can be exposed to a rotating magnetic field, and the phase lag between field and sample moment is studied. In magnetic particle spectroscopy (MPS), the harmonic spectrum of the MNP sample is measured in a large sinusoidal magnetic field. Examples for the realization of homogeneous binding experiments utilizing the different techniques will be presented. This work was supported by the FP 7 project NMP-2010-246479 and by the DFG via SFB 578.