267783 Trapping of Nanoparticles with Dielectrophoretic Nano-Probes

Tuesday, October 30, 2012: 1:02 PM
Fayette (Westin )
Nicholas R. Wood1, Amanda I. Wolsiefer1, Robert W. Cohn2 and Stuart J. Williams1, (1)Department of Mechanical Engineering, University of Louisville, Louisville, KY, (2)ElectroOptics Research Institute and Nanotechnology Center, University of Louisville, Louisville, KY

Silver gallium nano-probes have been used as dielectrophoretic electrodes to capture sub-micron colloids.  The silver gallium nano-probes were fabricated using a unique self-assembly method.  The nano-probes are crystalline structures that self-assemble at room temperature and pressure when thin films of elemental silver are introduced to micro-spheres of elemental gallium. The direction of the nano-probe assembly can be controlled by the geometry of the substrate on which they are grown.  The diameters of the nano-probes were measured to be approximately 100-500 nm.  Using nano-probes and ITO coverslips as electrodes, sub-micron colloids suspended in DI water and aqueous KCl were attracted and repelled using positive and negative dielectrophoretic forces at voltages of less than 1 VRMS.  Positive DEP forces successfully captured 200 nm fluorescent polystyrene particles as well as gold colloidal quantum dots as small as 5 nm in diameter.  Negative DEP forces were observed acting on fluorescent sub-micron polystyrene particles in solutions of various conductivity levels.

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