Dresden 2009 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 10: Biofluiddynamics

BP 10.2: Vortrag

Dienstag, 24. März 2009, 14:30–14:45, HÜL 186

Thermal Nanoparticle Traps: Theory and Experiment — Franz M. Weinert, Philipp Baaske, and •Dieter Braun — Systems Biophysics, Ludwig Maximilians University, Munich, Germany

In the past, we discussed theoretically that thermal gradients in porous rock can accumulate even single nucleic bases more than millionfold in centimeter-sized pore systems [1]. The accumulation is solely driven by a static vertical temperature gradient by convection and thermodiffusion.

We scaled down above mechanism by a factor of 1000. This is possible with light driven microflow [2][3] where the nonlinear combination of thermal expansion with temperature-dependent viscosity drives fluids remotely with a laser scanning microscope. As result we efficiently trap polystyrene beads with diameter of 40nm on the time scale of seconds.

In the future we envisage to combine the trap with the polymerase chain reaction. We previously showed that thermal convection can exponentially replicate DNA by PCR. With above approach we should be able to trap and replicate DNA in the same chamber, opening new possibilities for fast continuous in vitro evolution.

Publications:

[1] PNAS 104, 9346-9351 (2007)

[2] Physical Review Letters 100, 164501 (2008)

[3] Weinert & Braun, Journal of Applied Physics, in press.