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DY: Fachverband Dynamik und Statistische Physik

DY 26: Poster II

DY 26.23: Poster

Donnerstag, 26. März 2009, 16:00–18:00, P1A

Controllable selectivity in a microfluidic ratchet device: theory and experiment — •Christian Weß^1,2, Jan Regtmeier¹, Ralf Eichhorn², Peter Reimann², and Dario Anselmetti¹ — ¹Biophysics and Applied Nanoscience, Bielefeld University, Germany — ²Condensed Matter Theory, Bielefeld University, Germany

Three different species of micron sized particles were separated in a microfluidic device via electrodeless dielectrophoresis with controllable selectivity.

The experimental device consists of a linear channel containing an array of triangular non-conducting posts fabricated with polydimethylsiloxane (PDMS). AC and DC voltages are applied to induce electrophoretically driven migration and dielectrophoretic trapping at the posts. Subtle combinations of AC and DC pulse shapes were simulated numerically first in order to optimize selectivity and separation of the three particles species (1.2µ m, 1.9µ m and 2.9µ m in diameter). With the optimized parameters, we could demonstrate that we can selectively steer one arbitrary particle species in one direction, while the other two migrate into the opposite direction. The selectivity depends on particle size, charging and polarizability whereby we can trap and release specific particles from the traps which creates, under addition of the electrophoretical migration, net particle flows in the desired directions. The experimental results are in very good agreement with the numerical simulations, demonstrating the quality of the theoretical model. Next, the simulations and experiments will be extended to more particles species and possibly to cells.