Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 20: Nano-Biomaterials and Devices

AKB 20.6: Talk

Thursday, March 30, 2006, 11:30–11:45, ZEU 255

Light-induced Manipulation of DNA on Amorphous Silicon Surfaces — •M. Höb, S. Gatz, M. Stutzmann, and M. Brandt — Walter Schottky Institut, Technische Universität München, D-85748 Garching, Germany

Lab-on-a-chip devices depend on methods, which ideally are non-mechanical, to move, dispense, sort or mix (bio)chemical substances such as DNA. Electrokinetics is ideally suited to perform such functions, as the movement is induced and controlled by electric fields. We report a novel technique to manipulate DNA based on light-induced dielectrophoresis on hydrogenated amorphous silicon surfaces (a-Si:H), in which the coupling of an inhomogeneous ac electric field to the induced dipole moment of DNA allows the manipulation of the macromolecules. An otherwise unstructured a-Si:H/ZnO-layer sequence, which is locally illuminated, serves as a light-controlled ’virtual electrode’ to create the non-uniform electric field necessary in the electrolyte. Light-induced positive dielectrophoresis of the DNA molecules to the virtual electrode is observed by fluorescence microscopy. The attraction to the illuminated spot is studied as a function of frequency and amplitude of the applied ac voltage as well as the power density of the illumination.