(96d) DNA Electrophoresis through Nanopores

The voltage induced translocation of linear polyelectrolytes (such as DNA) through nanometer scale pores may be used as a basis for size separation. With further refinement it might be possible to extract more detailed information such as the sequence of bases from such experiments. The observables are the change in the magnitude and temporal duration of pore conductance during an individual translocation event. It is shown that these quantities may be reliably calculated by modeling a translocation event in terms of the electrophoresis of a charged cylinder along the axis of a cylindrically symmetric pore. Theoretical calculations are compared to data from single molecule experiments involving free translocations as well as force measurements using DNA immobilized within a nanopore by tethering it to a bead held in an optical trap.