Participating group members: |
Peter Reimann, Sebastian Getfert, Marc Fliedner |

Main cooperation partners: |
Dario Anselmetti, Jan Regtmeier, Lukas Bogunovic
(Biophysics and applied Nanoscience group at Bielefeld University
Ralf Eichhorn, NORDITA (Stockholm) |

The main objective of this joint SFB-project with the Biophysics and applied Nanoscience group at the University of Bielefeld is to exploit and/or develop new migration mechanisms for the purpose of the analytics (separation, purification, detection, lab-on-a-chip) of biomolecules in microfluidic systems. Our main focus is on time-dependent external forces beyond the quasi-stationary limit, generated by means of electrophoresis, dielectrophoresis, and fluid flows. Representative biomolecules like DNA and globular proteins in topographically and/or biochemically structured microfluidic systems are employed to test the theoretically predicted migration effects.

A typical example of such a new migration mechanism is a Brownian particle, diffusing in a suitably designed geometrical structure. Though far from equilibrium, its linear response to an external static force is a current, exactly as if it were at equilibrium. However, in the non-linear response regime, the particle slows down and then even starts to move in the direction opposite to the applied force. Typically, the stopping force at which this change of the migration direction occurs depends on particle properties like size or shape, opening new possibilities for the application in the separation of biomolecules.

Other examples are the selective acceleration of effective diffusion coefficients, ratchet effects, noise-induced collective phenomena far from equilibrium, and migration phenomena of driven polymers. Besides unraveling further new phenomena along these lines, our main emphasis is on specific experimental realizations of the predicted effects.

Typically we proceed along the following three steps:
(i) Theoretical identification and development of new transport concepts
and principles (qualitatively).
(ii) Their quantitative modelling and optimization
within the given experimental possibilities.
(iii) Their experimental realization by means of suitably structured
microfluidic devices and selected biomolecules.

Selected publications on negative mobility
(motion opposite to an applied force):

R. Eichhorn, P. Reimann, and P. Hänggi

*Brownian Motion exhibiting Absolute Negative Mobility*

Phys. Rev. Lett. **88**, 190601 (2002)

R. Eichhorn and P. Reimann

*Paradoxical non-linear response of a Brownian particle*

Phys. Rev. E, **70**, 035106(R) (2004)

R. Eichhorn and P. Reimann

*Paradoxical directed diffusion due to temperature anisotropies*

Europhys. Lett. **69**, 517 (2005)

A. Ros, R. Eichhorn, J. Regtmeier, T. T. Duong,
P. Reimann, and D. Anselmetti

*Absolute negative particle mobility*

Nature **436**, 928 (2005)

J. Regtmeier, R. Eichhorn, T. T. Duong, P. Reimann, D. Anselmetti, and A. Ros

* Pulsed-field separation of particles in a microfluidic device*

Eur. Phys. J. E **22**, 335 (2007)

J. Regtmeier, S. Grauwin, R. Eichhorn, P. Reimann, D. Anselmetti, and A. Ros

*Acceleration of absolute negative mobility*

J. Sep. Sci. **30**, 1461 (2007)

J. Nagel, D. Speer, T. Gaber, A. Sterck, R. Eichhorn, P. Reimann, K. Ilin, M. Siegel, D. Koelle, and R. Kleiner

* Observation of Negative Absolute Resistance in a Josephson Junction*

Phys. Rev. Lett. **100**, 217001 (2008)

R. Eichhorn, J. Regtmeier, D. Anselmetti, and P. Reimann

*Negative mobility and sorting of colloidal particles*

Soft Matter **6**, 1858 (2010)

Selected publications on the
acceleration and control of diffusion:

M. Schreier, P. Reimann, P. Hänggi, and E. Pollak

*Giant Enhancement of Diffusion and Particle Separation in Rocked
Periodic Potentials*

Europhys. Lett. **44**, 416 (1998)

P. Reimann, C. Van den Broeck, H. Linke, P. Hänggi, J.M. Rubi, and A. Perez-Madrid

*Giant Acceleration of Free Diffusion by use of Tilted Periodic Potentials*

Phys. Rev. Lett. **87**, 010602 (2001)

D. Reguera, P. Reimann, P. Hänggi, and J.M. Rubi

*Interplay of Frequency-synchronization with Noise: Current Resonances, giant Diffusion and Diffusion-crests*

Europhys. Lett. **57**, 644 (2002)

D. Reguera G. Schmid, P. S. Burada, J. M. Rubi
P. Reimann, and P. Hänggi,

*Entropic Transport: Kinetics, Scaling, and Control Mechanisms*

Phys. Rev. Lett. **96**, 130603 (2006)

M. Evstigneev, O. Zvyagolskaya, S. Bleil, R. Eichhorn, C. Bechinger, and P. Reimann

* Diffusion of colloidal particles in a tilted periodic potential: Theory versus experiment*

Phys. Rev. E **77**, 041107 (2008)

P. Reimann and R. Eichhorn

* Weak Disorder Strongly Improves the Selective Enhancement of Diffusion in a Tilted Periodic Potential*

Phys. Rev. Lett. **101**, 180601 (2008)

D. Speer, R. Eichhorn, and P. Reimann

*Anisotropic diffusion in square lattice potentials: giant enhancement and control*

EPL **97**, 60004 (2012)

Selected publications on further new migration concepts:

D. Speer, R. Eichhorn, and P. Reimann

* Directing Brownian Motion on a Periodic Surface*

Phys. Rev. Lett. **102**, 124101 (2009)

D. Speer, R. Eichhorn, and P. Reimann

* Exploiting Lattice Potentials for Sorting Chiral Particles*

Phys. Rev. Lett. **105**, 090602 (2010)

P. Tierno, P. Reimann, T.H. Johansen, and F. Sagues

* Giant Transversal Particle Diffusion in a Longitudinal Magnetic Ratchet*

Phys. Rev. Lett. **105**, 230602 (2010),
Physical Review Focus

L. Bogunovic, R. Eichhorn, J. Regtmeier, D. Anselmetti, and P. Reimann

* Particle sorting by a structured microfluidic ratchet device with tunable selectivity: theory and experiment*

Soft Matter **8**, 3900 (2012)

New subject: Translocation of DNA through nanopores

A. Spiering, S. Getfert, A. Sischka, P. Reimann, and D. Anselmetti

* Nanopore Translocation Dynamics of a Single DNA-Bound Protein
*

Nano Lett. **11**, 2978 (2011)

*Last modified on 2012-03-14*