Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 12: Single Molecules

BP 12.11: Talk

Wednesday, March 25, 2009, 12:45–13:00, HÜL 186

Microfluidic device for polarizability-quantification and fast DNA-separation on single molecule scales — •Lukas Bogunovic¹, Jan Regtmeier¹, Ralf Eichhorn², Alexandra Ros³, and Dario Anselmetti¹ — ¹Experimental Biophysics & Applied Nanoscience, Bielefeld University, Germany — ²Condensed Matter Theory, Bielefeld University, Germany — ³Department of Chemistry and Biochemistry, Arizona State University, Tempe, USA

We present a simple and easy to fabricate poly(dimethylsiloxane) (PDMS) microfluidic device, capable of quantifying DNA polarizabilities on a single molecule level. The same system is able to separate long DNA molecules as well as biotechnologically relevant supercoiled plasmid DNA via electrodeless dielectrophoresis in less than 240 seconds.

The device consists of a cross injector and an analysis channel. The latter is structured with a series of conducting posts creating dielectrophoretic (DEP) traps, when a voltage is applied. The quantificaton as well as the separation is consequently based on the size dependent thermally induced esacpes from those DEP traps.

The observed polarizabilities of linear dsDNA demonstrate a length dependence, which has been discussed controversially. This dependence can be described with a simple power law and an exponent for linear DNA from 6 kbp to 164 kbp close to the Flory exponent. In separation mode, separation times of 200s for λ (48.5 kbp)- and T2 (164 kbp)- DNA were achieved with baseline resolution.