ABSTRACT
In the past 20 years, nanopores have evolved into powerful and
versatile probes for the world of single biomolecules, allowing
scientists to detect them and discriminate between them with
remarkable precision with relatively lightweight instruments. The
basic concept follows the same idea as the Coulter counter [Coulter
(1953)], but scaled down to singlemolecules: The analyte of interest,
dissolved in an electrolyte solution, appears as a modulation of the
ion current when it crosses a small pore. The attention attracted
by these experiments would likely have been far smaller, if-only 4
years after seminal experiments had been published [Branton et al. (1996)]—it had not been found that solely based on the current
signal it is possible to distinguish single-stranded DNA (ssDNA)
molecules by their bases [Meller et al. (2000)]: The current blockade e.g., of poly(dC) was less pronounced than that of poly(dA). The
idea to build a nanopore-based read-out device, which sequentially
reads single DNA molecules, was born. This great leap for science
and medicine is not yet made, although many theoretical and
experimental hurdles that accompany this enterprise have been
cleared. Although DNA sequencing is themost prominent focal point
of ongoing research, also other applications in analytic chemistry or
clinical diagnosis are of significant interest.
