Berlin 2005 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
AKB: Biologische Physik
AKB 80: Microfluidics
AKB 80.1: Vortrag
Mittwoch, 9. März 2005, 11:45–12:00, TU H2013
Experimental Proof of Absolute Negative Mobility of Single Brownian Particles — •Jan Regtmeier1, Ralf Eichhorn2, Peter Reimann2, Dario Anselmetti1, and Alexandra Ros1 — 1Experimentelle Biophysik und Angewandte Nanowissenschaften,Universität Bielefeld, Universitätsstr. 25,33615 Bielefeld — 2Condensed Matter Theory,Universität Bielefeld,Universitätsstraße 25,33615 Bielefeld
Recently, it has been predicted theoretically [1] that the average motion of a single Brownian particle can be opposite to a small applied force. This behaviour, which seems to contradict Newtonian laws, is called Negative Mobility and can only occur far from thermodynamic equilibrium.
We experimentally demonstrate that negative mobility of non-interacting Brownian particles can be observed in periodic and symmetric potentials, forming a landscape of gaps and traps. Carboxylated polystyrene particles of 2 µm diameter in fact show an average motion against a static electric force in a poly(dimethylsiloxane) microfluidic device with micrometer sized periodically alternating structures using electrokinetic driving forces in physiological buffer solution. This setup enables high parallelisation and opens the way to use the system for biological applications such as separation of biomolecules or sorting of cells.
[1] R. Eichhorn, P. Reimann, P. Hänggi, Phys. Rev. Lett. 88, 190601 (2002)