Regensburg 2025 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 41: Poster III

MA 41.22: Poster

Donnerstag, 20. März 2025, 15:00–17:30, P3

3D Trajectory Tracking of Remote-Controlled Superparamagnetic Particles in Liquid — •Nikolai Weidt, Rico Huhnstock, Yahya Shubbak, and Arno Ehresmann — Department of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel

To develop Lab-on-a-chip systems, superparamagnetic particles (SPPs) can be surface-functionalized to specifically bind targeted analytes. A promising strategy for achieving analyte binding and transfer involves the directed transport of SPPs over magnetically stripe-patterned exchange bias layer systems. By precisely analyzing the three-dimensional trajectories of SPPs in this setup, we can detect events of analyte binding. To capture movement in the third dimension, we measure the defocusing of particles that exit the microscope's focal plane during transport steps. In this study, we quantify defocusing by calculating the Tenenbaum gradient (TG) for individual particles. This makes it possible to use a conventional light microscope combined with a piezo-controlled sample holder for 3D Trajectory tracking. Through a calibration process, we derive the z-coordinate of SPPs from the measured TG. The resulting 3D trajectories are validated through numerical simulations of SPP motion.

Keywords: lab-on-a-chip; bead; particle; transport; exchange bias