title: Dielectrophoretic trapping of nanoparticles with an electrokinetic nanoprobe.
abstract: A high aspect ratio 3D electrokinetic nanoprobe is used to trap polystyrene particles (200 nm), gold nanoshells (120 nm), and gold nanoparticles (mean diameter 35 nm) at low voltages (<1 V(rms)). The nanoprobe is fabricated using room temperature self-assembly methods, without the need for nanoresolution lithography. The nanoprobe (150-500 nm in diameter, 2-150 μm in length) is mounted on the end of a glass micropipette, enabling user-specified positioning. The nanoprobe is one electrode within a point-and-plate configuration, with an indium-tin oxide cover slip serving as the planar electrode. The 3D structure of the nanoprobe enhances dielectrophoretic capture; further, electro-hydrodynamic flow enhances trapping, increasing the effective trapping region. Numerical simulations show low heating (1 K), even in biological media of moderate conductivity (1 S/m).
authors.affiliation: Department of Mechanical Engineering, University of Louisville, Louisville, KY, USA.
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Wood
authors.forename: Amanda I
authors.initials: AI
authors.lastname: Wolsiefer
authors.forename: Robert W
authors.initials: RW
authors.lastname: Cohn
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Williams
mesh_terms: D003198:Computer Simulation; D004586:Electrophoresis / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D057446:Hydrodynamics; D053768:Metal Nanoparticles / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000379:methods*; D008855:Microscopy, Electron, Scanning; D015335:Molecular Probes / Q000737:chemistry; D011137:Polystyrenes / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D015335:Molecular Probes; D011137:Polystyrenes; D006046:Gold
keywords: Colloids; Dielectrophoresis; Electrohydrodynamics; Nano-particles; Nanoneedle