Dielectrophoretic tweezers for examining particle-surface interactions within microfluidic devices

S W. Lee, Department of Biomedical Engineering, Yonsei University
Haibo Li, SanDisk Corporation
Rashid Bashir, Birck Nanotechnology Center and Bindley Bioscience Center, Purdue University

Abstract

The authors present dielectrophoresis (DEP)-based tweezers that can be used to characterize the interactions between a particle and the surface it is attached to, within a microfluidic device. As a proof of concept, 5.4 mu m polystyrene beads functionalized by carboxyl group were attached on a bare and poly-L-lysine functionalized oxide surface. Negative dielectrophoresis force was generated using interdigitated electrodes and the peak dielectrophoresis voltage where the beads were repelled away from the surface was used to characterize the strength of interaction between the particle and the surface. Electric field and DEP force calculation were used to corroborate the measured results.