Detecting DNA Folding with Nanocapillaries

We demonstrate for the first time the detection of the folding state of double-stranded DNA in nanocapillaries with the resistive pulse technique We show that glass capillaries can be pulled into nanocapillaries with diameters down to 45 nm We study translocation of lambda-DNA which is driven by an electrophoretic force through the nanocapillary The resulting change in ionic current indicates the folding state of single lambda-DNA molecules Our experiments prove that nanocapillaries are suitable for label-free analysis of DNA in aqueous solutions and viable alternatives to solid-state nanopores made by silicon nanotechnology