Keyser Lab at the Cavendish. The Keyser lab has capitalized on an astoundingly simple (= cheap!) way of producing nanopores. They heat a glass microcapillary with a laser and use the traditional glass pulling technique to obtain a sharp tip. Internal diameters of 10-100 nanometers can be obtained in this way. The experiment shows the force signal as a trapped DNA is gradually pulled out of the pore. The force can be calculated using the lubrication theory [5,6] for electrokinetics and is shown by the red dots in the lower panel.
These experiments give us confidence that the principal resistive force in DNA translocation does indeed arise primarily from hydrodynamic drag in the pore region. The challenge now is to use this knowledge to evolve new tools for characterizing DNA such as the base sequence, interactions with proteins and fundamental questions related to the behavior of DNA as a charged polymer. This is still an open book with many exciting possibilities in basic science as well as in nascent technologies. Already, a new term is being used in this context "DNA Force Spectroscopy"!
Acknowledgement: My research in this area has been supported by the NIH (USA) and by the Leverhulme Trust (UK).
 Optical tweezers for force measurements on DNA in nanopores (2006) UF Keyser, J van der Does, C Dekker & NH Dekker Rev. Sci. Instruments 77 (10)
 Electrokinetic-flow-induced viscous drag on a tethered DNA inside a nanopore (2007) S Ghosal Physical Review E 76 (6), 061916
 Single macromolecules under tension and in confinement (PhD thesis, Cambridge University) Oliver Otto 2011
 Lubrication theory for electro-osmotic flow in a microfluidic channel of slowly varying cross-section and wall charge (2002) S Ghosal Journal of Fluid Mechanics 459, 103-128
 Electrophoresis of a polyelectrolyte through a nanopore (2006) S Ghosal Physical Review E 74 (4), 041901
 Effect of salt concentration on the electrophoretic speed of a polyelectrolyte through a nanopore (2007) S Ghosal Physical review letters 98 (23), 238104