Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 18: Polyelectrolytes

CPP 18.4: Vortrag

Dienstag, 24. März 2009, 10:15–10:30, ZEU 114

Optimizing end-labeled free-solution electrophoresis by increasing the hydrodynamic friction of the drag-tag — •Kai Grass¹, Christian Holm², and Gary Slater³ — ¹FIAS, Goethe-University Frankfurt, Ruth-Moufang-Strasse 1, 60438 Frankfurt, Germany — ²ICP, University of Stuttgart, Pfaffenwaldring 27, 70569 Stuttgart, Germany — ³University of Ottawa, 150 Louis-Pasteur, Ottawa, Ontario K1N 6N5, Canada

We study the electrophoretic separation of polyelectrolytes of varying length in free-solution by means of end-labeled free-solution electrophoresis (ELFSE). A coarse-grained molecular dynamics simulation model, using full electrostatic interactions and a mesoscopic Lattice Boltzmann fluid to account for hydrodynamic interactions, is used to characterize the drag coefficients of different label types: linear and branched polymeric labels, as well as transiently bound micelles.

It is specifically shown that the label's drag coefficient is determined by its hydrodynamic size, and that the drag per label monomer is largest for linear labels. However, the addition of side chains to a linear label offers the possibility to increase the hydrodynamic size, without having to increase the linear length of the label, thereby simplifying synthesis. The third class of labels investigated, transiently bound micelles, seems very promising for the usage in ELFSE, as they provide a significant higher hydrodynamic drag than the other label types.

The results are compared to recent experimental results, as well as to theoretical predictions, and it is analyzed how the efficiency of the ELFSE method can be improved by using smartly designed drag-tags.