Here's a quick overview: The DNA strand is attracted to an enzyme that is part of the electrophysiological fluid. In turn, the enzyme is attracted to a nanopore, in which it lodges. The enzyme is engineered to unzip the double-helix structure of the DNA strand so that one strand is directed back into the fluid, while the other enters the nanopore for sequencing. More amazing is that the enzyme incorporates a ratcheting structure, so the single DNA strand does not pass quickly through the nanopore, but rather advances one base pair at a time. The rate at which the DNA strand passes through the nanohole is controlled by the magnitude of the unobstructed ionic current, and can be as large as 15 base pairs per second. Better accuracy is associated with slower rates.