Regensburg 2022 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Poster 2

BP 12.66: Poster

Tuesday, September 6, 2022, 17:30–19:30, P4

Investigation of nonlinear effects on polarizable µbeads in AC/DC-Dielectrophoresis — •Tim R. Baumann, Dario Anselmetti, and Martina Viefhues — Experimental Biophysics & Applied Nanosciences, Department of Physics, Bielefeld University

Dielectrophoresis (DEP) is a common selective force used for separation applications in microfluidics. Due to a non-uniform electric field, polarizable particles migrate through a fluid. Depending on the applied electric field, intrinsic parameters like surface charge, polarizability or ion mobility and extrinsic parameters like pH-value objects lead to acceleration, deceleration or trapping in dielectrophoretic potentials. Thus, analysis of the migration in electric fields yields access to characteristic electric parameter of particles. The direction of movement is given by the value of charge and the direction of the electric field. Here a constant direct current (DC) is set in range 0−40 V and incrementally raised by 5 V to drive the beads through a microfluidic device. An alternating current (AC) (f=1 kHz) ranging from 100−450 V in amplitude (increment size: 50 V) was superimposed to generate dielectrophoretic trapping forces that should decelerate the beads. An increase of migration velocity was observed though, which is assumed to be due to higher order terms of the electric field as recently presented by the group of Perez-Gonzales for DC electric fields [1]. In this work, we investigate if this effect also applies in AC electric fields. [1]Anal. Chem. 2020, 92, 12871-12879