Berlin 2008 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 2: DNA and Chromatin
BP 2.7: Vortrag
Montag, 25. Februar 2008, 12:15–12:30, PC 203
Conformational DNA separation by dielectrophoresis — •Jan Regtmeier1, Ralf Eichhorn2, Alexandra Ros1, and Dario Anselmetti1 — 1Experimental Biophysics & Applied Nanoscience, Bielefeld University, Universitaetsstr. 25, 33615 Bielefeld, Germany — 2Condensed Matter Theory, Bielefeld University, Universitaetsstr. 25, 33615 Bielefeld, Germany
In modern biotechnology and pharmaceutics applications, topologically closed circular DNA plays an important role. For instance, plasmids are used as genetic vectors in DNA recombinants, and for in vivo gene therapy. The latter makes high purification and exact characterization of plasmid DNA indispensable.
We extend our previous studies [1] and present the separation of DNA fragments with equal number of base pairs according to their conformation (supercoiled from linear DNA fragments). The separation is performed in a microfluidic poly(dimethylsiloxane) (PDMS) chip within 210 s. The device consists of a cross injector and a microstructured separation channel with a periodic array of nonconducting posts. The application of an AC voltage induces dipoles in the DNA molecules, which couple to the inhomogeneous electric field in the post array (dielectrophoretic trapping). Superimposed application of a DC voltage induces DNA migration and separation, based on differences in DNA polarizabilities. A detailed analysis of the trapping times allows quantification of the DNA polarizabilities.
[1] Dielectrophoretic Manipulation of DNA: Separation and Polarizability, J. Regtmeier et al., Anal. Chem. 79, 3925-3932 (2007)