Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Poster Session III

CPP 33.33: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster C

Molecular AC electrokinetics using interdigitated electrodes — •Eva-Maria Laux¹, Christian Wenger², Frank F. Bier¹, and Ralph Hölzel¹ — ¹Fraunhofer IZI-BB, Potsdam, Germany — ²IHP GmbH - Leibniz Institute for Innovative Microelectronics, Frankfurt (Oder), Germany

Electrokinetic effects are universally applicable to particles regardless of their charge and - in principle - of their size. However, as a consequence of the interference of thermal motion, a successful manipulation of particles in the nanometer range calls for increasingly high electric field gradients. These can be produced by further miniaturized electrode structures, Here we use interdigitated nanoelectrodes made of tungsten, embedded in silicon dioxide, fabricated on a silicon substrate. Whilst the electrode width and gap width are 750 nm and 450 nm, respectively, the thickness amounts to 100 nm and the curvature of the electrode edges - which is the decisive parameter for dielectrophoretic action - is below 50 nm.

Using these electrodes, we attracted fluorescent proteins (eGFP) to the electrodes and achieved immobilization as well as alignment of the protein molecules. With its cylindric shape with 2.4 nm diameter and 4.2 nm height, eGFP belongs to the smallest objects manipulated by AC electrokinetics up to date. We are pushing this limit further by handling, as an example, the fluorescence dye rhodamine 6G, which has a diameter of approx. 1 nm. The dye molecules are indeed attracted towards the electrode structures and accumulated in the electrode gaps as revealed by fluorescence microscopy.