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AKB: Biologische Physik

AKB 30: Poster Session I

AKB 30.28: Poster

Montag, 27. März 2006, 15:30–18:00, P1

Nanoelectrode Arrays for On-Chip Manipulation of Organic Substances and Proteins in Aqueous Solutions — •Cheng-Ping Luo, Andreas Heeren, Wolfgang Henschel, and Dieter P. Kern — Institute of Applied Physics, University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany

Dielectrophoresis is a convenient method for manipulation of dielectric substances in liquid. Since organic and biological substances are mostly dielectric, they can be trapped in or released from a specific area by applying electrical signals of proper frequency and amplitude to an appropriate set of electrodes. In our previous experiments, AC signals were applied to microelectrodes. In the case of positive dielectrophoresis, dielectric substances congregated in the gaps between electrodes, especially at edges, in which the field intensities are strongest. However, for substances at the nanoscale, higher fields are required. Then turbulence due to electro-osmosis flow, which is caused by non-uniform electric field and electrical double layer and is proportional to the square of the applied voltage, will strongly disturb the movement and arrangement of the substances. In this work, devices based on dielectrophoresis using nanoelectrode arrays have been investigated to reduce the electro-osmosis flow. Nanoscale organic substances and biomolecules in aqueous solution, for example, polystyrene beads, bovine serum albumin and antibody molecules, were successfully trapped between the nanoelectrodes. Furthermore, the results demonstrate that the required applied voltage can be reduced by a factor of five in comparison with those using microelectrodes.