Figure 3.

Translocation of bacteriophage lambda DNA (48.5 kbp) through nanopores (diameters ~ 15 nm). (a) An Al₂O₃ coated ion beam sculpted nanopore: final diameter ~15 nm, length ~40 nm. Each current blockage event represents a single DNA molecule passing through the pore. Two such events are enlarged from the several-second recording (arrows) and displayed in large scale. (b) An Al₂O₃ coated FIB pore: final diameter ~15 nm, length ~250 nm. The DNA translocates in similar time duration but causes smaller current blockage because of greater pore length of the FIB-coated pore. The enhanced portion of some blockages (within the dashed elipses) reflects a portion of the translocating DNA molecule that is folded on itself, such that two strands of the double-helix occupy the nanopore simultaneously.⁸ Translocation was driven by a 300 mV voltage bias.