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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 51: Poster Session III-2

CPP 51.4: Poster

Dienstag, 17. März 2020, 14:00–16:00, P2/EG

Interplay of surface forces for the directed transport of superparamagnetic beads above a thin film layer substrate — •Katharina Getfert, Rico Huhnstock, Dennis Holzinger, and Arno Ehresmann — Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel

Directed transport of biofunctionalised magnetic particles over a substrate is a promising mechanism for sensitive analyte detection in lab-on-a-chip devices. Former publications present the realization of controllable superparamagnetic particle transport above a magnetically stripe patterned Exchange-Bias thin film layer substrate, revealing a complex interaction of surface forces between the particles and the substrate [1]. The interplay of these forces determines the steady state distance between both components, which is an important factor for the transport properties. In this work the influence of surface forces on the colloidal stability and, thus, on the particle transport is investigated. The impact on transport properties due to modifications in electrostatic and magnetic interactions between particle and substrate is analyzed by detecting the particle velocity. It can be shown, that the pH-value and thereby the ion-concentration of the surrounding medium plays an essential role in stabilization of the transport system due to its effects on the electrostatic interaction. Furthermore, the increase of the attractive magnetic interaction provides a higher sensitivity in measuring electrolyte dependent transport property changes.

[1] Ehresmann et al. (2015), Sensors, 15: 28854-28888.