Dresden 2026 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 36: Molecular Magnetism and Magnetic Particles / Clusters I

MA 36.4: Vortrag

Mittwoch, 11. März 2026, 15:45–16:00, POT/0151

Making molecular changes visible using near-surface transport of micron-sized magnetic particles — •Yahya Shubbak, Nikolai Weidt, Arne Vereijken, Rico Huhnstock, and Arno Ehresmann — Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany

Transport of magnetic particles (MPs) in liquid close to the surface of a flat substrate containing a periodic magnetic domain pattern is a promising lab-on-a-chip (LOC) technology for detecting MP-bound analytes, even when their size is negligible compared to the MP size. As proof of principle, we show that simple observation of MP motion via optical microscopy is sufficient to distinguish MPs of the same nominal size, but surface-functionalized with two different functional groups. The different surface chemistry changes the liquid-mediated MP-to-substrate forces acting during close-to-surface transport, resulting in significant variations in the experimentally observable MP velocity. More specifically, superparamagnetic MPs measuring 2 micrometre in diameter with a polymer coating of solely carboxyl (COOH) end groups, or a mixture of carboxyl and amino (NH2) groups, respectively, have been studied. Transport of these MPs above a magnetic stripe domain pattern in double-distilled water showed a remarkable difference in their average velocities, rendering the COOH-functionalized MPs almost twice as fast as the NH2 counterparts for otherwise identical experimental parameters. This result enables the magnetophoretic separation of MPs based on their surface properties.

Keywords: Magnetic Particles; Lab on a chip; Magnetic Substrates; Molecular changes